A store clerk sold 25 maths books and 10 english books for $855.00 .if she sold 10 maths books and 40 English books, she would have got $135 more. calculate the cost of each book.

Question

A store clerk sold 25 maths books and 10 english books for $855.00  .if she sold 10 maths books and 40 English books, she would have got $135 more. calculate the cost of each book.

drwls · Answer

Let m be the math book cost (in dollars) and e be the english book cost (also in dollars). Solve these two equations simultaneously:
25m + 10e = 855
10m + 40e = 855 + 135 = 990

100m + 40e = 3420

90m = 2430
m = 27