Question

What value of x makes this proportion true 3/x=15/40

Answer 1

3/x=15/40
solve for x
multiply both sides by x
3=15x/40
multiply both sides by 40
120=15x
dvide both sdies by 15
8=x

the answer is 8

or you could simplifyy 15/40 to get 3/8

Answer 2

If you would like to solve the equation 3 / x = 15 / 40 for x, you can calculate this using the following steps:

3 / x = 15 / 40     /*x
3 = 15 / 40 * x    /*40
3 * 40 = 15 * x   /15
x = 3 * 40 / 15
x = 8

The correct result would be 8.