Eric has 20-cent coins and 50-cent coins. The total value of all his coins is $20. He has 19 less 20-cent coins than 50-cent coins. How many coins does he have altogether?
| |
20-cent |
50-cent |
Total |
| Number |
1 u |
1 u + 19 |
2 u + 19 |
| Value |
20 |
50 |
|
| Total value |
20 u |
50 u + 950 |
70 u + 950 |
$1 = 100¢
$20 = 20 x 100 = 2000¢
Eric has 19 more 50-cent coins than 20-cent coins.
Number of 20-cent coins = 1 u
Number of 50-cent coins = 1 u + 19
Total value of 20-cent coins
= 20 x 1 u
= 20 u
Total value of 50-cent coins
= 50 x (1 u + 19)
= 50 u + 950
Total value of the coins
= 20 u + 50 u + 950
= 70 u + 950
70 u + 950 = 2000
70 u = 2000 - 950
70 u = 1050
1 u = 1050 ÷ 70 = 15
Total number of coins
= 1 u + (1 u + 19)
= 2 u + 19
= 2 x 15 + 19
= 30 + 19
= 49
Answer(s): 49
