Vincent has 20-cent coins and 50-cent coins. The total value of all his coins is $27. He has 5 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 + 5 |
2 u + 5 |
| Value |
20 |
50 |
|
| Total value |
20 u |
50 u + 250 |
70 u + 250 |
$1 = 100¢
$27 = 27 x 100 = 2700¢
Vincent has 5 more 50-cent coins than 20-cent coins.
Number of 20-cent coins = 1 u
Number of 50-cent coins = 1 u + 5
Total value of 20-cent coins
= 20 x 1 u
= 20 u
Total value of 50-cent coins
= 50 x (1 u + 5)
= 50 u + 250
Total value of the coins
= 20 u + 50 u + 250
= 70 u + 250
70 u + 250 = 2700
70 u = 2700 - 250
70 u = 2450
1 u = 2450 ÷ 70 = 35
Total number of coins
= 1 u + (1 u + 5)
= 2 u + 5
= 2 x 35 + 5
= 70 + 5
= 75
Answer(s): 75
