Main content

## Rational number word problems

# Rational number word problem: cosmetics

CCSS.Math:

## Video transcript

Jess recently started a business
producing cosmetic products made from natural ingredients. She wants to
advertise her products by distributing bags of
samples in her neighborhood. She calculated that it
takes her two minutes to prepare each bag. How many hours--
they give us minutes here, now they want
hours-- how many hours will it take to prepare
1,200 bags of samples if she asks seven friends
to help her with her work? So the one thing we
could think about is, how long would it take
her to do it by herself? So it takes her, by herself,
two minutes per bag. And then we have 1,200 bags,
not 12 bags, 1,200 bags which means it's going to
take her two minutes for each of the 1,200 bags. Well that's 2 times
1,200 is 2,400 minutes. Now that's if she was just
working on it by herself, but she's got seven friends. And we can assume
that they would all take about two minutes
to prepare each bag. Now this is a little
bit tricky because you might want to divide
this by 7 saying, hey, we're going to have seven
times as many people. But you remember, she
asks seven friends so there's actually
eight people involved. There's Jess and
her seven friends. So it's actually going
to be eight times faster than if Jess did it by herself. This is if she only
had one person. If you're going to
have eight people, you are going to take
eight times less time. So with eight people, it's
going to be 2,400 divided by 8 is 300 minutes. And we're almost done, except
for the fact that they asked for our answer in
terms of hours. So 300 minutes is
how many hours? Well you have 60
minutes per hour so you could say 300
minutes-- I'll just write min for short-- divided
by 60 minutes per hour gives us 300 divided
by 60 is 5 hours. So it will take Jess and her
seven friends, a total of eight people, five hours to prepare
all of her sample bags.