Xavier bought 4 colouring books. The original price of each colouring book was $28. He was given 5% discount on the first colouring book and 25% discount on the rest of the colouring books. How much did he pay for the 4 colouring books altogether?
Cost of the first colouring book after 5% discount in percent
= 100% - 5%
= 95%

Cost of the first colouring book after discount
= 95% x 28
= ⁹⁵₁₀₀ x 28
= $26.60

Number of the rest of the colouring books that enjoyed 25% discount
= 4 - 1
= 3

Cost of each of the rest of the 3 colouring books after 25% discount in percent
= 100% - 25%
= 75%

Cost of each of the rest of the 3 colouring books
= 75% x 28
= ⁷⁵₁₀₀ x 28
= $21

Cost of the rest of the 3 colouring books that enjoyed 25% discount
= 3 x 21 
= $63

Total cost for the 4 colouring books
= 26.60 + 63
= $89.60

Answer(s): $89.60