SOLUTION: A cashier's drawer has some $5 bills, some $10 bills, and some $20 bills. There are 15 bills worth a total of $185. How many $5 bills, $10 bills, and $20 bills are there?

Algebra ->  Equations -> SOLUTION: A cashier's drawer has some $5 bills, some $10 bills, and some $20 bills. There are 15 bills worth a total of $185. How many $5 bills, $10 bills, and $20 bills are there?      Log On


   



Question 234693: A cashier's drawer has some $5 bills, some $10 bills, and some $20 bills. There are 15 bills worth a total of $185. How many $5 bills, $10 bills, and $20 bills are there?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let number of 5's = a
Let number of 10's = b
Let number of 20's = c
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given:
5a+%2B+10b+%2B+20c+=+185
a+%2B+b+%2B+c+=+15
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there are 3 unknowns and only 2 equations, so
it requires some extra work to solve
Let me figure out how many 20's I should have
to give me 15 bills in all
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20 ---- 10 ---- 5 ----# of bills
--------------------------------
10 ($200, too much)
9 ----- 0 ----- 1 ---- 10 (not enough)
8 ----- 0 ----- 5 ---- 13 (not enough)
7 ----- 1 ----- 7 ---- 15 OK
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There are 7 $20's, 1 $10 and 7 $5's
check answer:
5a+%2B+10b+%2B+20c+=+185
5%2A7+%2B+10%2A1+%2B+20%2A7+=+185
35+%2B+10+%2B+140+=+185
185+=+185
and
a+%2B+b+%2B+c+=+15
7+%2B+1+%2B+7+=+15
15+=+15
OK