PSLE Vaidev saved a total of $65 in coins in his coin box.
710 of all the coins saved were one-dollar coins. There were 4 times as many one-dollar coins as fifty-cent coins. The remaining coins were twenty-cent coins. How many coins did Vaidev save in his coin box altogether?
|
One-dollar |
Fifty-cent |
Twenty-cent |
Total |
Comparison between the number of 3 types of coins |
7x4 28 u |
3x4 12 u |
10x4 40 u
|
Comparison between the number of one-dollar and fifty-cent coins |
4x7 |
1x7 |
|
|
Number |
28 u |
7 u |
5 u |
40 u |
Value |
1 |
0.5 |
0.2 |
|
Number x value |
28 u |
3.5 u |
1 u |
32.5 u |
Number of $1 coins is the repeated identity.
Make the number of $1 coins the same.
LCM of 7 and 4 = 28
Total value of coins = 32.5 u
32.5 u = 65
1 u = 65 ÷ 32.5 = 2
Total number of coins
= 28 u + 7 u + 5 u
= 40 u
= 40 x 2
= 80
Answer(s): 80