PSLE Jack saved a total of $107 in coins in his coin box.
19 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 Jack save in his coin box altogether?
|
One-dollar |
Fifty-cent |
Twenty-cent |
Total |
Comparison between the number of 3 types of coins |
1x4 4 u |
8x4 32 u |
9x4 36 u
|
Comparison between the number of one-dollar and fifty-cent coins |
4x1 |
1x1 |
|
|
Number |
4 u |
1 u |
31 u |
36 u |
Value |
1 |
0.5 |
0.2 |
|
Number x value |
4 u |
0.5 u |
6.2 u |
10.7 u |
Number of $1 coins is the repeated identity.
Make the number of $1 coins the same.
LCM of 1 and 4 = 4
Total value of coins = 10.7 u
10.7 u = 107
1 u = 107 ÷ 10.7 = 10
Total number of coins
= 4 u + 1 u + 31 u
= 36 u
= 36 x 10
= 360
Answer(s): 360