PSLE Justin had a total of 16 coins in his coin box.
14 of all the coins saved were one-dollar coins. There were 2 times as many one-dollar coins as fifty-cent coins. The remaining coins were twenty-cent coins. What was the total value of all the coins in his coin box?
|
One-dollar |
Fifty-cent |
Twenty-cent |
Total |
Comparison between the number of 3 types of coins |
1x2 2 u |
3x2 6 u |
4x2 8 u
|
Comparison between the number of one-dollar and fifty-cent coins |
2x1 |
1x1 |
|
|
Number |
2 u |
1 u |
5 u |
8 u |
Value |
1 |
0.5 |
0.2 |
|
Number x value |
2 u |
0.5 u |
1 u |
3.5 u |
Number of $1 coins is the repeated identity.
Make the number of $1 coins the same.
LCM of 1 and 2 = 2
Total number of coins = 8 u
8 u = 16
1 u = 16 ÷ 8 = 2
Total value of coins
= 2 u 0.5 u 1 u
= 3.5 u
= 3.5 x 2
= $7
Answer(s): $7