Oliver has 5-cent coins and 10-cent coins. The total value of all his coins is $23. He has 8 less 5-cent coins than 10-cent coins. How many coins does he have altogether?
|
5-cent |
10-cent |
Total |
Number |
1 u |
1 u + 8 |
2 u + 8 |
Value |
5 |
10 |
|
Total value |
5 u |
10 u + 80 |
15 u + 80 |
$1 = 100¢
$23 = 23 x 100 = 2300¢
Oliver has 8 more 10-cent coins than 5-cent coins.
Number of 5-cent coins = 1 u
Number of 10-cent coins = 1 u + 8
Total value of 5-cent coins
= 5 x 1 u
= 5 u
Total value of 10-cent coins
= 10 x (1 u + 8)
= 10 u + 80
Total value of the coins
= 5 u + 10 u + 80
= 15 u + 80
15 u + 80 = 2300
15 u = 2300 - 80
15 u = 2220
1 u = 2220 ÷ 15 = 148
Total number of coins
= 1 u + (1 u + 8)
= 2 u + 8
= 2 x 148 + 8
= 296 + 8
= 304
Answer(s): 304