ME NEEDS SOME HELP WITH MATH PLS

If 10 men take 18 days to mow 60 acres of grass, how long will 15 men take to mow 80 acres?

In a two-digit number the units' digit is 7 more than the tens' digit. the number with digits reversed is three times as large as the sum of the original number and the two digits. find the number.

Given abc find the values of x and y. in your final answer, include all of your calculations.