Question

Candy selling at six dollars per pound will be mixed with candy selling at nine dollars per pound how many pounds of more expensive candy are needed to produce a 15 pound mixture that sells for seven dollars per pound

Answer 1

The 15 lbs at $7=$105

So multiple 5x9 as a test and check results. 105-45=60

Here you can see that 60 is a factor of 6 by 10 so you got lucky and got the answer of 10lbs at $6 & 5lbs at $9=15 lbs at $7 average