PSLE Oscar saved a total of $77 in coins in his coin box.
25 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 ten-cent coins. How many coins did Oscar save in his coin box altogether?
|
One-dollar |
Fifty-cent |
Ten-cent |
Total |
Comparison between the number of 3 types of coins |
2x3 6 u |
3x3 9 u |
5x3 15 u
|
Comparison between the number of one-dollar and fifty-cent coins |
3x2 |
1x2 |
|
|
Number |
6 u |
2 u |
7 u |
15 u |
Value |
1 |
0.5 |
0.1 |
|
Number x value |
6 u |
1 u |
0.7 u |
7.7 u |
Number of $1 coins is the repeated identity.
Make the number of $1 coins the same.
LCM of 2 and 3 = 6
Total value of coins = 7.7 u
7.7 u = 77
1 u = 77 ÷ 7.7 = 10
Total number of coins
= 6 u + 2 u + 7 u
= 15 u
= 15 x 10
= 150
Answer(s): 150