Question

48487 x 7

Answer 1

a1=20
a2=20*1/4
a3=a2*1/4=20*1/4*1/4 = 20*1/4^2
a4=a3*1/4=20*1/4*1/4*1/4=20*1/4^3
a5=a4*1/4=20*1/4*1/4*1/4*1/4=20*1/4^4
in general
an=20*1/4^(n-1)

Answer 2

anyway add up the first 5 terms