Matt has twice as many quarters as dimes in his coin collection. If the dimes and quarters together total $9.00 how many of each kind of coin does he have?

Answer 1

.10*(1/2)x+.25x = 9.00
x(.10*(1/2)+.25)= 9.00
x= 9.00
___(.10*(1/2)+.25)
x = 30
Since you times the dimes by 1/2, you take half of x.
So Dimes = 15, and Quarters = 30
Check, .10(15)+ .25(30) = 9.00