Riordan has 5-cent coins and 50-cent coins. The total value of all his coins is $22. He has 11 less 5-cent coins than 50-cent coins. How many coins does he have altogether?
| |
5-cent |
50-cent |
Total |
| Number |
1 u |
1 u + 11 |
2 u + 11 |
| Value |
5 |
50 |
|
| Total value |
5 u |
50 u + 550 |
55 u + 550 |
$1 = 100¢
$22 = 22 x 100 = 2200¢
Riordan has 11 more 50-cent coins than 5-cent coins.
Number of 5-cent coins = 1 u
Number of 50-cent coins = 1 u + 11
Total value of 5-cent coins
= 5 x 1 u
= 5 u
Total value of 50-cent coins
= 50 x (1 u + 11)
= 50 u + 550
Total value of the coins
= 5 u + 50 u + 550
= 55 u + 550
55 u + 550 = 2200
55 u = 2200 - 550
55 u = 1650
1 u = 1650 ÷ 55 = 30
Total number of coins
= 1 u + (1 u + 11)
= 2 u + 11
= 2 x 30 + 11
= 60 + 11
= 71
Answer(s): 71
