Carl has 10-cent coins and 50-cent coins. The total value of all his coins is $25. He has 2 less 10-cent coins than 50-cent coins. How many coins does he have altogether?
|
10-cent |
50-cent |
Total |
Number |
1 u |
1 u + 2 |
2 u + 2 |
Value |
10 |
50 |
|
Total value |
10 u |
50 u + 100 |
60 u + 100 |
$1 = 100¢
$25 = 25 x 100 = 2500¢
Carl has 2 more 50-cent coins than 10-cent coins.
Number of 10-cent coins = 1 u
Number of 50-cent coins = 1 u + 2
Total value of 10-cent coins
= 10 x 1 u
= 10 u
Total value of 50-cent coins
= 50 x (1 u + 2)
= 50 u + 100
Total value of the coins
= 10 u + 50 u + 100
= 60 u + 100
60 u + 100 = 2500
60 u = 2500 - 100
60 u = 2400
1 u = 2400 ÷ 60 = 40
Total number of coins
= 1 u + (1 u + 2)
= 2 u + 2
= 2 x 40 + 2
= 80 + 2
= 82
Answer(s): 82