George has 20-cent coins and 50-cent coins. The total value of all his coins is $16. He has 4 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 + 4 |
2 u + 4 |
Value |
20 |
50 |
|
Total value |
20 u |
50 u + 200 |
70 u + 200 |
$1 = 100¢
$16 = 16 x 100 = 1600¢
George has 4 more 50-cent coins than 20-cent coins.
Number of 20-cent coins = 1 u
Number of 50-cent coins = 1 u + 4
Total value of 20-cent coins
= 20 x 1 u
= 20 u
Total value of 50-cent coins
= 50 x (1 u + 4)
= 50 u + 200
Total value of the coins
= 20 u + 50 u + 200
= 70 u + 200
70 u + 200 = 1600
70 u = 1600 - 200
70 u = 1400
1 u = 1400 ÷ 70 = 20
Total number of coins
= 1 u + (1 u + 4)
= 2 u + 4
= 2 x 20 + 4
= 40 + 4
= 44
Answer(s): 44