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Algebra2 word problem
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# Algebra2 word problem

[From: ] [author: ] [Date: 11-05-06] [Hit: ]
you need another equation that involves \$2.35.We know that if we multiply n number of nickles by 0.05 and q number of quarters by 0.25, and then add them together,......
Luis received 15 coins from his dad for chores around the house. Some coins were quarters and others were nickels. If he earned \$2.35, how many coins were nickels?

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Let n = nickels
Let q = quarters

We know that that there are 15 coins if you add the n number of nickles and q number of quarters together. So...
n + q = 15

Now, you need another equation that involves \$2.35. We know that if we multiply n number of nickles by 0.05 and q number of quarters by 0.25, and then add them together, we will get \$2.35. Translate that into a form of equation and you get:

0.05n + 0.25q = 2.35

Now to solve for the number of nickles, which is n, you need those two equations I just gave:

n + q = 15
0.015n + 0.25q = 2.35

Next is solve for q using the first equation.

n + q = 15
q = -n + 15

Plug whatever q is (which is -n + 15) in the "q" on the second equation:

0.05n + 0.25q = 2.35
0.05n + 0.25(-n + 15) = 2.35
0.05n - 0.25n + 3.75 = 2.35
-0.2n = -1.4
n = -1.4 / -0.2
n = 7

There were 7 nickles.

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