Julian has 10-cent coins and 20-cent coins. The total value of all his coins is $22. He has 11 less 10-cent coins than 20-cent coins. How many coins does he have altogether?
|
10-cent |
20-cent |
Total |
Number |
1 u |
1 u + 11 |
2 u + 11 |
Value |
10 |
20 |
|
Total value |
10 u |
20 u + 220 |
30 u + 220 |
$1 = 100¢
$22 = 22 x 100 = 2200¢
Julian has 11 more 20-cent coins than 10-cent coins.
Number of 10-cent coins = 1 u
Number of 20-cent coins = 1 u + 11
Total value of 10-cent coins
= 10 x 1 u
= 10 u
Total value of 20-cent coins
= 20 x (1 u + 11)
= 20 u + 220
Total value of the coins
= 10 u + 20 u + 220
= 30 u + 220
30 u + 220 = 2200
30 u = 2200 - 220
30 u = 1980
1 u = 1980 ÷ 30 = 66
Total number of coins
= 1 u + (1 u + 11)
= 2 u + 11
= 2 x 66 + 11
= 132 + 11
= 143
Answer(s): 143