If you're seeing this message, it means we're having trouble loading external resources on our website.

If you're behind a web filter, please make sure that the domains *.kastatic.org and *.kasandbox.org are unblocked.

# GMAT: Math 3

12-19, pgs. 153-154. Created by Sal Khan.

## Want to join the conversation?

• I have the 12th edition book which does not have no. 14 and 16 problem. Can someone please give the questions? Thanks
• 14. Which Cannot be a value of 1/1-x?
16. What is the combined area, in square inches, of the front and back of a rectangular sheet of paper measuring 8.5 by 11 inches.

I have a PDF version of the 11th edition. I'd be happy to email it to you if you like.
• Sorry, in problem number 16, Why is 187 the answer? should´t it be 187*2 in order to be both areas combined?
• i am in 6th grade soorry but could you put a little more slower problems
(1 vote)
• At the beginning of question 13, Sal talks about the Khan application, is he referring to an iphone application? If so, which one?
• For problem 15, is the answer 4 rolls or 4 dozens? The questions was about rolls.
• question number 15 says how many dozens of rools are remain after one half plus 80% of one half arer sold which means half of 40 dozens is 20 and 80 percent of the remaining 20 is 16 so 4 dozen rolls remain not 4 rolls.
• Is this correct:

1/0-1 = -1

Zero minus 1 = negative one. Negative one into one equals negative one.
• The question focuses on the value of the expression, not value of X.
Is there an X that can result in the expression to be equal to -1? Yes, when X=0, expression is -1. So this is not our answer. Move to next option.
Is there an X that can result in the expression to be equal to 0? No. Because this can happen only when X is infinity which cannot be written as a number. So 0 is a value that the expression can never have, hence this is the right answer.
• on number 17 you said 30 then 36