Ivory saved two coins every day from Monday to Sunday by putting them into a tin can. Each coin was either a 5¢ or 50¢ coin. The total value of the coins at the end of 2 weeks was $11.30. How many of the coins were 50¢ coins?
| 50¢ |
Value of 50¢ |
5¢ |
Value of 5¢ |
Total value |
28
|
28 x 50¢ =
1400¢ |
0 |
0 x 5¢ =
0 |
1400¢ |
27
|
27 x 50¢ =
1350¢ |
1 |
1 x 5¢ =
5¢ |
1355¢ |
22
|
22 x 50¢ =
1100¢ |
6
|
6 x 5¢ =
30¢ |
1130¢ |
$1 = 100¢
$11.30 = 1130¢
Number of coins in one week
= 2 x 7
= 14
Number of coins in 2 weeks
= 2 x 14
= 28
Total amount saved if all the coins were 50¢
= 28 x 50
= 1400¢
Big difference between the total values of 50¢ coins and 5¢ coins
= 1400 - 1130
= 270¢
Small difference between the value of one 50¢ coin and one 5¢ coin
= 50 - 5
= 45¢
Number of 5¢ coins
= 270 ÷ 45
= 6
Number of 50¢ coins
= 28 - 6
= 22
Answer(s): 22
