Cody has a total of 15 fifty-cent and twenty-cent coins. The total value of the coins is $6. If he spends all the fifty-cent coins on a marker, how much does the marker cost?
Number of
fifty-cent coins |
Value of
fifty-cent coins |
Number of
twenty-cent coins |
Value of
twenty-cent coins |
Total
value |
| 15 |
15 x 50
= 750¢ |
0 |
0 |
750¢ |
| 14 |
14 x 50
= 700¢ |
1 |
1 x 20
= 20¢ |
720¢ |
| 10 |
10 x 50
= 500¢ |
5 |
5 x 20
= 100¢ |
600¢ |
$1 = 100¢
$6 = 600¢
Total value if all the coins are fifty-cent coins
= 15 x 50
= 750¢
Big difference between the value of fifty-cent coins and twenty-cent coins
= 750 - 600
= 150¢
Small difference between the value of one fifty-cent coin and one twenty-cent coin
= 50 - 20
= 30¢
Number of twenty-cent coins
= 150 ÷ 30
= 5
Number of fifty-cent coins
= 15 - 5
= 10
Cost of the marker
= 10 x 50
= 500¢
= $5
Answer(s): $5
