Question

maria has 20 coins in her pocket and all of her coins are either quarters or dimes. the coins total $3.20. how many of each coin does she have?

Answer 1

Let x be the No. of quarters coins
Let y be the No. of dimes.
Then maria has 20 coins in her pocket means x+y=20
But, quarters means 1/25 of dollar and dime means 1/10 of a dollar
Hence, x*(1/25)+y*(1/10)=3.20
Solve for x& y
x+y=20
x*(1/25)+y*(1/10)=3.20