SOLUTION: betty has $2.20 in dimes and quarters. If the number of dimes is 1/4 the number of quarters, how many dimes does she have.

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Question 395291: betty has $2.20 in dimes and quarters. If the number of dimes is 1/4 the number of quarters, how many dimes does she have.
Answer by jrfrunner(365) About Me  (Show Source):
You can put this solution on YOUR website!
you have two unknowns d=number of dimes and q=number of quarters
so you need two equations to find the two unknowns
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given
eq1: d=1/4q or 4d=q
eq2: 0.1d+0.25d=2.20
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multiply eq2 by 100 to eliminate decimals
10d+25d=220
10d+25(4d)=220 substitute 4d=q
110d=220
d=220/110=2 or 2 dimes
since q=4d then 8 quarters