Xavier has 10-cent coins and 50-cent coins. The total value of all his coins is $17. He has 10 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 + 10 |
2 u + 10 |
Value |
10 |
50 |
|
Total value |
10 u |
50 u + 500 |
60 u + 500 |
$1 = 100¢
$17 = 17 x 100 = 1700¢
Xavier has 10 more 50-cent coins than 10-cent coins.
Number of 10-cent coins = 1 u
Number of 50-cent coins = 1 u + 10
Total value of 10-cent coins
= 10 x 1 u
= 10 u
Total value of 50-cent coins
= 50 x (1 u + 10)
= 50 u + 500
Total value of the coins
= 10 u + 50 u + 500
= 60 u + 500
60 u + 500 = 1700
60 u = 1700 - 500
60 u = 1200
1 u = 1200 ÷ 60 = 20
Total number of coins
= 1 u + (1 u + 10)
= 2 u + 10
= 2 x 20 + 10
= 40 + 10
= 50
Answer(s): 50