PSLE Peter saved a total of $261 in coins in his coin box.
712 of all the coins saved were one-dollar coins. There were 3 times as many one-dollar coins as fifty-cent coins. The remaining coins were twenty-cent coins. How many coins did Peter save in his coin box altogether?
|
One-dollar |
Fifty-cent |
Twenty-cent |
Total |
Comparison between the number of 3 types of coins |
7x3 21 u |
5x3 15 u |
12x3 36 u
|
Comparison between the number of one-dollar and fifty-cent coins |
3x7 |
1x7 |
|
|
Number |
21 u |
7 u |
8 u |
36 u |
Value |
1 |
0.5 |
0.2 |
|
Number x value |
21 u |
3.5 u |
1.6 u |
26.1 u |
Number of $1 coins is the repeated identity.
Make the number of $1 coins the same.
LCM of 7 and 3 = 21
Total value of coins = 26.1 u
26.1 u = 261
1 u = 261 ÷ 26.1 = 10
Total number of coins
= 21 u + 7 u + 8 u
= 36 u
= 36 x 10
= 360
Answer(s): 360