A certain fraction has the value 3/4. If its numerator is decreased by 7 and its denominator is increase by 4, the resulting fraction has the value 1/2. Find the original fraction

n = 16 - 7

n = 9

Step-by-step explanation:

If the numerator of a fraction is increased by 3, the fraction becomes 3/4."

Cross multiply

4(n+3) = 3d

4n + 12 = 3d

"If the denominator is decreased by 7, the fraction becomes 1."

Cross multiply

1n = d - 7

n = (d-7)

In the 1st equation replace n with d-7

4(d-7) + 12 = 3d

4d - 28 + 12 = 3d

4d - 3d - 16 = 0

d = 16 is the denominator

then n = 16 - 7

n = 9

9/16 =  the original equation

the answer is  

a.

4,624π mm2

step-by-step explanation: