the average of marks obtained by 120 boys was 38 . if the average of marks of passed boys was 39 and that of failed boys was 15 , the number of boys who passed the examination is ?
n0 = 120.0
n1 = 38.0
n2 = 39.0
n3 = 15.0
t0 = n0 * n1
t1 = n0 * n3
t2 = n2 - n3
t3 = t0 - t1
answer = t3 / t2
print(answer)