Ryan has a total of 18 fifty-cent and ten-cent coins. The total value of the coins is $5. 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
ten-cent coins |
Value of
ten-cent coins |
Total
value |
| 18 |
18 x 50
= 900¢ |
0 |
0 |
900¢ |
| 17 |
17 x 50
= 850¢ |
1 |
1 x 10
= 10¢ |
860¢ |
| 8 |
8 x 50
= 400¢ |
10 |
10 x 10
= 100¢ |
500¢ |
$1 = 100¢
$5 = 500¢
Total value if all the coins are fifty-cent coins
= 18 x 50
= 900¢
Big difference between the value of fifty-cent coins and ten-cent coins
= 900 - 500
= 400¢
Small difference between the value of one fifty-cent coin and one ten-cent coin
= 50 - 10
= 40¢
Number of ten-cent coins
= 400 ÷ 40
= 10
Number of fifty-cent coins
= 18 - 10
= 8
Cost of the marker
= 8 x 50
= 400¢
= $4
Answer(s): $4
