The same number is added to both numerator and denominator of the fraction 15/31. If the resulting fraction is 5/6 what is the number?

the number is 65

Step-by-step explanation:

the same number is added. so let the number be 'x'

the equation can hence be written as:

15 + x / 31 + x = 5 / 6

(now cross multiply)

6 (15 + x) = 5 (31 + x)

90 + 6x = 155 + 5x

6x - 5x = 155 - 90

x = 65