PSLE Ian saved a total of $28 in coins in his coin box.
13 of all the coins saved were one-dollar coins. There were 3 times as many one-dollar coins as ten-cent coins. The remaining coins were fifty-cent coins. How many coins did Ian save in his coin box altogether?
|
One-dollar |
Ten-cent |
Fifty-cent |
Total |
Comparison between the number of 3 types of coins |
1x3 3 u |
2x3 6 u |
3x3 9 u
|
Comparison between the number of one-dollar and ten-cent coins |
3x1 |
1x1 |
|
|
Number |
3 u |
1 u |
5 u |
9 u |
Value |
1 |
0.1 |
0.5 |
|
Number x value |
3 u |
0.1 u |
2.5 u |
5.6 u |
Number of $1 coins is the repeated identity.
Make the number of $1 coins the same.
LCM of 1 and 3 = 3
Total value of coins = 5.6 u
5.6 u = 28
1 u = 28 ÷ 5.6 = 5
Total number of coins
= 3 u + 1 u + 5 u
= 9 u
= 9 x 5
= 45
Answer(s): 45