PSLE Vaidev saved a total of $57 in coins in his coin box.
49 of all the coins saved were one-dollar coins. There were 2 times as many one-dollar coins as ten-cent coins. The remaining coins were fifty-cent coins. How many coins did Vaidev save in his coin box altogether?
|
One-dollar |
Ten-cent |
Fifty-cent |
Total |
Comparison between the number of 3 types of coins |
4x1 4 u |
5x1 5 u |
9x1 9 u
|
Comparison between the number of one-dollar and ten-cent coins |
2x2 |
1x2 |
|
|
Number |
4 u |
2 u |
3 u |
9 u |
Value |
1 |
0.1 |
0.5 |
|
Number x value |
4 u |
0.2 u |
1.5 u |
5.7 u |
Number of $1 coins is the repeated identity.
Make the number of $1 coins the same.
LCM of 4 and 2 = 4
Total value of coins = 5.7 u
5.7 u = 57
1 u = 57 ÷ 5.7 = 10
Total number of coins
= 4 u + 2 u + 3 u
= 9 u
= 9 x 10
= 90
Answer(s): 90