Question

HELP

Answer 1

Attachment?

Answer 2

This is constant percent rate problem, so let's use percent change formula.

Percent Change = (V2 -V1)/V1 x 100

month 0 = 80 books
month 1 = 100 book

P.C. = (100 - 80)/80 x 100 ===> 20/80 x 100
P.C. = 25%

month 2 = ?
100 x 1.25 ==> 125

month 3 = ?
125 x 1.25 ==> 156.25

month 4 =?
156.25 x 1.25 ==> 244.141

month 5 =
244.141 x 1.25 ==> 305.176

month 6 =
305.176 x 1.25 ==> 381.470

month 7 =
381.470 x 1.25 ==> 476.837

month 8 =
476.837 x 1.25 ==> 596