Would the equation m = 60 + 7.60b - 7.60 also work?

Yes that would work too since the books always costs $7.60 each with a membership. You have to buy at least 1 book, though, since the membership fee is always $60, and you would have no reason to get the membership if you weren't going to buy any books. On the SAT, though, you have to go with the answer choices they give you, and the best one in this case is m = 60 + 7.60(b-1).

What if the student decides not to buy any book? Then we have zero book which will reduce the membership fee i.e(0-1). I don't understand that

You are completely right! The equation works if the student actually buys one or more books. It is only true when b ≥ 1.

At 0:50, I don't get it isn't a free book by definition a book that you don't buy? They asked for the amount of money a student spend after BUYING b books and yearly membership.

b books is the total of books that you buy, including the first one. But the first one is free, so you don´t pay it, so it isn't a book that you don't buy it. you have it, you just don´t pay for it

hey why are the comments so old. didnt the digi SAT begin this year ?

it did, but the syllabus for math didn't change much so most of the math videos for digital sat are reused from the paper pen version

If Lee pays $72 in advance on his account at the movie store. Every time he rents a movie, $4 is deducted from his account for every movie rented. How can I write a linear function that models the value remaining in his account after renting x movies. Find the value remaining after renting 4 movies.

If we want to write a linear function that represents this, the first thing to discuss is what you want x and y to be. The question tells us that y should be the account's value, and x should be the number of movies rented. From here, all we do is fill out slope-intercept form (y = mx+b). We're given two numbers: $72 in advance (aka before any movies are bought), and $4 deducted per movie. Since the slope is given in units of y-per-x, it looks like we're going to be using -4 for slope and 72 for y-intercept. To find the value remaining after renting 4 movies, you could either count backwards from 72 by 4's or set 4 for x and solve for y: y = -4x + 72 y = -4(4) + 72 y = $56

I do not understand why c is not the right choice. I am confused as to why you need to subtract b-1

The first book is free, so you substract that book from b, the amount of books you bought.

At 1:40, what if b is zero? (Like we buy the membership but haven't bought any books yet) The yearly membership cost will be reduce?

Since this is a real world problem, (0-1 = -1) -1 books doesn't make sense. So your statement is invalid.

Main content

Course: Digital SAT Math > Unit 6

Lesson 3: Linear relationship word problems: medium

Linear function word problems — Basic example

Name: Linear function word problems — Basic example
Uploaded: 2015-04-16T17:46:08Z
Description: Watch Sal work through a basic Linear functions word problem.

Google Classroom

Watch Sal work through a basic Linear functions word problem.

Want to join the conversation?

Sort by:

pstewart57759
Posted 7 months ago. Direct link to pstewart57759's post “Man I wanna go home.”
Man I wanna go home.
Button navigates to signup pageComment on pstewart57759's post “Man I wanna go home.”
(115 votes)
Answer
- Jonathan Chau
  Posted 6 months ago. Direct link to Jonathan Chau's post “type sh”
  type sh
  Comment on Jonathan Chau's post “type sh”
  (35 votes)
baochauais
Posted 9 years ago. Direct link to baochauais's post “At 1:40, what if b is zer...”
At
1:40
, what if b is zero? (Like we buy the membership but haven't bought any books yet) The yearly membership cost will be reduce?
Button navigates to signup pageComment on baochauais's post “At 1:40, what if b is zer...”
(0 votes)
Answer
- Shubhang Jani
  Posted 8 years ago. Direct link to Shubhang Jani's post “Since this is a real worl...”
  Since this is a real world problem, (0-1 = -1) -1 books doesn't make sense. So your statement is invalid.
  Comment on Shubhang Jani's post “Since this is a real worl...”
  (16 votes)
timnyce2
Posted 7 years ago. Direct link to timnyce2's post “Would the equation m = 60...”
Would the equation m = 60 + 7.60b - 7.60 also work?
Button navigates to signup pageButton navigates to signup page
(8 votes)
Answer
- Brian Smith
  Posted 7 years ago. Direct link to Brian Smith's post “Yes that would work too s...”
  Yes that would work too since the books always costs $7.60 each with a membership. You have to buy at least 1 book, though, since the membership fee is always $60, and you would have no reason to get the membership if you weren't going to buy any books. On the SAT, though, you have to go with the answer choices they give you, and the best one in this case is m = 60 + 7.60(b-1).
  Button navigates to signup page
  (11 votes)
Prasun Guragain
Posted 6 years ago. Direct link to Prasun Guragain's post “At 1:04, he meant to say ...”
At
1:04
, he meant to say 15.20 but he actually said 14.20
Button navigates to signup pageComment on Prasun Guragain's post “At 1:04, he meant to say ...”
(11 votes)
Answer
- Woon Na
  Posted 6 years ago. Direct link to Woon Na's post “Its in the caption bubble...”
  Its in the caption bubble thing yes you are right
  Button navigates to signup page
  (1 vote)
Ajibola Favour
Posted 6 years ago. Direct link to Ajibola Favour's post “What if the student decid...”
What if the student decides not to buy any book? Then we have zero book which will reduce the membership fee i.e(0-1). I don't understand that
Button navigates to signup pageButton navigates to signup page
(6 votes)
Answer
- Sarah K.
  Posted 6 years ago. Direct link to Sarah K.'s post “You are completely right!...”
  You are completely right! The equation works if the student actually buys one or more books. It is only true when b ≥ 1.
  Comment on Sarah K.'s post “You are completely right!...”
  (8 votes)
zoya0512edu
Posted a year ago. Direct link to zoya0512edu's post “hey why are the comments ...”
hey why are the comments so old. didnt the digi SAT begin this year ?
Button navigates to signup pageComment on zoya0512edu's post “hey why are the comments ...”
(5 votes)
Answer
- Arjun Sharma
  Posted a year ago. Direct link to Arjun Sharma's post “it did, but the syllabus ...”
  it did, but the syllabus for math didn't change much so most of the math videos for digital sat are reused from the paper pen version
  Button navigates to signup page
  (8 votes)
roni.danaf
Posted 8 years ago. Direct link to roni.danaf's post “At 0:50, I don't get it i...”
At
0:50
, I don't get it isn't a free book by definition a book that you don't buy? They asked for the amount of money a student spend after BUYING b books and yearly membership.
Button navigates to signup pageComment on roni.danaf's post “At 0:50, I don't get it i...”
(6 votes)
Answer
- febveicer
  Posted 8 years ago. Direct link to febveicer's post “b books is the total of b...”
  b books is the total of books that you buy, including the first one. But the first one is free, so you don´t pay it, so it isn't a book that you don't buy it. you have it, you just don´t pay for it
  Button navigates to signup page
  (5 votes)
Vincent Schliebs
Posted a year ago. Direct link to Vincent Schliebs's post “If Lee pays $72 in advanc...”
If Lee pays $72 in advance on his account at the movie store. Every time he rents a movie, $4 is deducted from his account for every movie rented. How can I write a linear function that models the value remaining in his account after renting x movies. Find the value remaining after renting 4 movies.
Button navigates to signup pageComment on Vincent Schliebs's post “If Lee pays $72 in advanc...”
(5 votes)
Answer
- Hecretary Bird
  Posted a year ago. Direct link to Hecretary Bird's post “If we want to write a lin...”
  If we want to write a linear function that represents this, the first thing to discuss is what you want x and y to be. The question tells us that y should be the account's value, and x should be the number of movies rented. From here, all we do is fill out slope-intercept form (y = mx+b). We're given two numbers: $72 in advance (aka before any movies are bought), and $4 deducted per movie. Since the slope is given in units of y-per-x, it looks like we're going to be using -4 for slope and 72 for y-intercept.
  To find the value remaining after renting 4 movies, you could either count backwards from 72 by 4's or set 4 for x and solve for y:
  y = -4x + 72
  y = -4(4) + 72
  y = $56
  Comment on Hecretary Bird's post “If we want to write a lin...”
  (6 votes)
Rocky 666
Posted 9 years ago. Direct link to Rocky 666's post “I do not understand why c...”
I do not understand why c is not the right choice. I am confused as to why you need to subtract b-1
Button navigates to signup pageComment on Rocky 666's post “I do not understand why c...”
(4 votes)
Answer
- chloe.paula.weber
  Posted 9 years ago. Direct link to chloe.paula.weber's post “The first book is free, s...”
  The first book is free, so you substract that book from b, the amount of books you bought.
  Comment on chloe.paula.weber's post “The first book is free, s...”
  (8 votes)
Siegward of Catarina
Posted 7 months ago. Direct link to Siegward of Catarina's post “At 0:00, Praise the Sun!”
At
0:00
, Praise the Sun!
Button navigates to signup pageComment on Siegward of Catarina's post “At 0:00, Praise the Sun!”
(5 votes)
Answer

Video transcript

- [Instructor] We're told Fara watched two different TV shows last week. TV show A has 11-minute episodes, and TV show B has 43-minute episodes. Together, she spent 196 minutes watching TV shows. Which equation models this relationship, where lowercase a is the number of TV show A episodes and lowercase b is the number of TV show B episodes Fara watched? So pause this video and have a go at it on your own before we work through this together. All right, now, let's do this together. So we know that together, she spent 196 minutes watching TV shows. So what we wanna do is total the amount of time she spent watching TV show A, the amount of time she spent watching TV show B, and then that should be equal to 196. And so, actually, let me just do TV show A in this orange color. How much time did she spend watching TV show A? Well, we know that each episode of TV show A is 11 minutes. So it's going to be 11 minutes times the number of episodes. And they said that lowercase a is the number of TV show A episodes. So this right over here, 11a, is how much time she spent watching TV show A. And what about TV show B? Well, each episode is 43 minutes. So it's going to be 43 minutes per episode. And how many episodes are there of TV show B? Well, it's lowercase b is the number of TV show B episodes. So 43 minutes per episode times lowercase b episodes, that's how much time she spent watching TV show B. So if you add the amount of time she watched TV show A to the amount of time she spent watching TV show B, that will be her total time, and we know that that needs to be equal to 196. And so let's see which of these choices have it. That's not that one. Let's see, this one is it, exactly what we got. This is different, and this is different. And we're done.