Pierre has 20-cent coins and 50-cent coins. The total value of all his coins is $32. He has 8 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 + 8 |
2 u + 8 |
| Value |
20 |
50 |
|
| Total value |
20 u |
50 u + 400 |
70 u + 400 |
$1 = 100¢
$32 = 32 x 100 = 3200¢
Pierre has 8 more 50-cent coins than 20-cent coins.
Number of 20-cent coins = 1 u
Number of 50-cent coins = 1 u + 8
Total value of 20-cent coins
= 20 x 1 u
= 20 u
Total value of 50-cent coins
= 50 x (1 u + 8)
= 50 u + 400
Total value of the coins
= 20 u + 50 u + 400
= 70 u + 400
70 u + 400 = 3200
70 u = 3200 - 400
70 u = 2800
1 u = 2800 ÷ 70 = 40
Total number of coins
= 1 u + (1 u + 8)
= 2 u + 8
= 2 x 40 + 8
= 80 + 8
= 88
Answer(s): 88
