PSLE Justin had a total of 60 coins in his coin box.
16 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 ten-cent coins. What was the total value of all the coins in his coin box?
|
One-dollar |
Fifty-cent |
Ten-cent |
Total |
Comparison between the number of 3 types of coins |
1x2 2 u |
5x2 10 u |
6x2 12 u
|
Comparison between the number of one-dollar and fifty-cent coins |
2x1 |
1x1 |
|
|
Number |
2 u |
1 u |
9 u |
12 u |
Value |
1 |
0.5 |
0.1 |
|
Number x value |
2 u |
0.5 u |
0.9 u |
3.4 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 = 12 u
12 u = 60
1 u = 60 ÷ 12 = 5
Total value of coins
= 2 u 0.5 u 0.9 u
= 3.4 u
= 3.4 x 5
= $17
Answer(s): $17