Question

the campus bookshop sells exercise books and textbooks, where, the total cost of 10 exercise books and 2 textbooks is $1400.00. One also finds the total cost of 3 textbooks and 30 exercise books is $3000. Then determine the price of 1 exercise book?

Answer 1

The price of 1 exercise book is $122.45.

Explanation:

This question is solved using a system of equations.

I am going to say that:

x is the price of one exercise book.

y is the price of one textbook.

Total cost of 10 exercise books and 2 textbooks is $1400.00.

This means that:

`10x + 2y = 1400`

Since we want x:

`2y = 1400 - 10x`

`y = 700 - 5x`

One also finds the total cost of 3 textbooks and 30 exercise books is $3000.

This means that:

`3x + 30y = 3000`

Since
`y = 700 - 5x`

`3x + 30(700 - 5x) = 3000`

`3x + 21000 - 150x = 3000`

`147x = 18000`

`x = (18000)/(147)`

`x = 122.45`

The price of 1 exercise book is $122.45.