Riordan has 5-cent coins and 50-cent coins. The total value of all his coins is $17. He has 12 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 + 12 |
2 u + 12 |
Value |
5 |
50 |
|
Total value |
5 u |
50 u + 600 |
55 u + 600 |
$1 = 100¢
$17 = 17 x 100 = 1700¢
Riordan has 12 more 50-cent coins than 5-cent coins.
Number of 5-cent coins = 1 u
Number of 50-cent coins = 1 u + 12
Total value of 5-cent coins
= 5 x 1 u
= 5 u
Total value of 50-cent coins
= 50 x (1 u + 12)
= 50 u + 600
Total value of the coins
= 5 u + 50 u + 600
= 55 u + 600
55 u + 600 = 1700
55 u = 1700 - 600
55 u = 1100
1 u = 1100 ÷ 55 = 20
Total number of coins
= 1 u + (1 u + 12)
= 2 u + 12
= 2 x 20 + 12
= 40 + 12
= 52
Answer(s): 52