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DerKrebs [107]
3 years ago
15

Mary has a collection of nickels and quarters for a total of $4.90. If she has 42 coins in total, how many of each kind are ther

e?
Mathematics
1 answer:
damaskus [11]3 years ago
5 0

Answer:

14 quarters and 28 nickels

Step-by-step explanation:

System of Equations where x = number of quarters and y = number of nickels

(1) equation with value of each coin

    0.25(x)+0.05(y) = 4.90

(2) total number of coins

    x + y = 42

Solve system of equations using either substitution or elimination

(elimination multiplying equation 2 by -0.5)

.25(x) + 0.05(y) = 4.90

-0.05(x) - 0.05(y) = 42 * (-0.05)

(3) Resulting equation

.20(x) = 2.8

x = 14

plug x into equation 2

14 + y = 42

y = 28

There are 14 quarters and 28 nickels in Mary's collection.

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5 0
3 years ago
Please help . 20 points for right answer
siniylev [52]
You would add up the percentages first, which would bring everything up to 35%. You would then take the original cost of the item, which is $30 and multiple it by the 35%. 

The equation would look like...

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Your final answer is $19.50. :) Which isn't a bad deal if I say so myself.
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