Sam has exactly 18.90 in dimes and quarters, with an equal number of dimes and quarters. He spends five quarters and twice as many dimes at the convenience store, and he spends 55 cents at the donut shop. If he pays the exact amount for everything, how many quarters does Sam have left?
number of dimes --- x
number of quarters --- x
10x + 25x = 1890
x = 54
to get 55 cents in quarters and dimes --- 1 quarter + 3 dimes
is the only way
so he spent 6 quarts, and has 48 quarters left
(don't know what "If he pays the exact amount for everything" is supposed
to mean)
checking it all out:
he spends 5 quarters and 10 dimes at convenience store
= 1.25 + 1.00 = 2.25
spends 55 cents at donut shop (don't know what you can buy there for 55 cents....)
total spent = 2.80, leaving him with 16.10
coins left:
quarters = 54-5-1 = 48
dimes left = 54-10-3 = 41
money left = 48(.25) + 41(.1) = 16.10
my answer is correct