Question

a bag contains forty coins, all of them either 2 cent or 5 cent coins. If the value of the money in the bag is $1.55, find the number of each kind.

Answer 1

Let the number of coins of $2$ cents be $x$

Let the number of coins of $5$ cents be $y$

Total no. of coins $=40x+y=40y=40-x\cdots \left(1\right)$

The value of coins is $1552x+5y=1552x+5(40-x)=1552x+200-5x=155-3x=-45x=15⟹y=35$

so there are $15-2$ cents coins and $35-5$ cents coins