Question

The denominator of the fraction 4/15 is increased by an amount so that the value of the resulting fraction is 1/5. Determine the amount by which the denominator was increased.

Answer 1

4/15 -> 3/15
-1/15 is the increase.
Where did you go from there?

Answer 2

4/15 + a = 1/5

multiply both sides by 15:

4 + 15a = 1

15a = -3

a = -3/15

a = -1/5

Answer 3

4+15a=3
15a=-1
a=-1/15