A collection of 108 coins containing only quarters and nickels is worth $21. A table titled Coin Collection showing Number of Coins, Value, and Total. The first row shows Nickels, and has n, 0.05, and 0.05 n. The second row shows, Quarters, and has q, 0.25, and 0.25 q. The third row shows total, and has not entries. Which value could replace q on the chart? 21 108 21 – n 108 – n

q = 108-n

Step-by-step explanation:

Given: 108 coins containing only quarters and nickels

q = 108-n

since total number of coins is 108, and n= number of nickels

If you want to know how many of each kind of coin, read on:

First solve the number of quarters and nickels.

If all 108 coins are quarters, the value is 108*0.25 = $27

Since this value exceed the actual by 27-21 = $6,

we replace a number of quarters by nickels.

Each replacement will reduce the value by 25 - 5 = 20 cents = 0.2 dollars.

So it will take 6/0.2 = 30 replacements.

Therefore there are 108-35 = 78 quarters and 30 nickels.