Kelvin had some money. If he buys 3 books, he will have $12 left. If he buys 5

books, he will be short of $4. Find the cost of a book.

Guest Dec 29, 2021

#3**0 **

*Kelvin had some money. If he buys 3 books, he will have $12 left. If he buys 5*

*books, he will be short of $4. Find the cost of a book.*

Let M stand for Kelvin's money, and let B stand for the price of a book.

M – 3B = 12 (equation 1)

M – 5B = –4 (equation 2)

Subtract eq 2 from eq 1

2B = 16 which means B = 8 i.e., **The cost of one book is $8.**

You can go on to determine that Kelvin started with $36 but the problem doesn't ask for that.

_{.}

Guest Dec 29, 2021