How do you explain how to do this math problem to a child?

7/10 of the U.S. population (175,104,000)in 1991 believed saying A to be true. What is the total population? We are trying to find what the whole population total is. They have given us 7/10 or 1755,104,00. How do we get the whole? Thanks.

6 answers

7/10 times an unknown number can be written as (7/10)x

(7/10)x = 175,104,000

Divide 175,104,000 by 7/10

175,104,000 / 7/10 = 175,104,000 * 10/7

1,751,040,000 / 7 = 250,148,571
You can set up a ratio and cross-multiply:
http://www.worldplenty.com/rat.htm

7/10 = 175104000/x

Cross-multiply and solve for x.
IDK EVEN HAVE A CLUE!!! I AM ALSO A FIFTH GRADER AND I LOOKED ONLINE TO SEE THE ANSWER AND THATS HOW I GOT HERE!!
Thank you! I was leading my child on another route! I still don't get it but shucks, she was closer to it than me. She was gonna multiply instead of divide. Ugh!
This is soooo helpful I had no idea how to do this
are you ms. sue teacher in texas