PSLE Andy had a total of 108 coins in his coin box.
512 of all the coins saved were one-dollar coins. There were 3 times as many one-dollar coins as twenty-cent coins. The remaining coins were fifty-cent coins. What was the total value of all the coins in his coin box?
|
One-dollar |
Twenty-cent |
Fifty-cent |
Total |
Comparison between the number of 3 types of coins |
5x3 15 u |
7x3 21 u |
12x3 36 u
|
Comparison between the number of one-dollar and twenty-cent coins |
3x5 |
1x5 |
|
|
Number |
15 u |
5 u |
16 u |
36 u |
Value |
1 |
0.2 |
0.5 |
|
Number x value |
15 u |
1 u |
8 u |
24 u |
Number of $1 coins is the repeated identity.
Make the number of $1 coins the same.
LCM of 5 and 3 = 15
Total number of coins = 36 u
36 u = 108
1 u = 108 ÷ 36 = 3
Total value of coins
= 15 u 1 u 8 u
= 24 u
= 24 x 3
= $72
Answer(s): $72