smc

Question

Cindy was asked by her teacher to subtract 3 from a certain number and then divide the result by 9. Instead, she subtracted 9 and then divided the result by 3, giving an answer of 43. What would her answer have been had she worked the problem correctly?

Accepted Answer

We work backwards; the number that Cindy started with is 3(43)+9=138. Now, the correct result is 138-39=1359=15. Our answer is 15.