if x / 4 years ago roger was 21 years old and x / 4 years from now he will be 4 x years old , how old will he be 5 x years from now ?
n0 = 4.0
n1 = 21.0
n2 = 4.0
n3 = 4.0
n4 = 5.0
t0 = n0 * n4
t1 = n1 - 1.0
t2 = t1 / 2.0
t3 = n0 * t0
answer = t3 - t2
print(answer)