PSLE Jack had a total of 280 coins in his coin box.
37 of all the coins saved were one-dollar coins. There were 4 times as many one-dollar coins as twenty-cent coins. The remaining coins were ten-cent coins. What was the total value of all the coins in his coin box?
|
One-dollar |
Twenty-cent |
Ten-cent |
Total |
Comparison between the number of 3 types of coins |
3x4 12 u |
4x4 16 u |
7x4 28 u
|
Comparison between the number of one-dollar and twenty-cent coins |
4x3 |
1x3 |
|
|
Number |
12 u |
3 u |
13 u |
28 u |
Value |
1 |
0.2 |
0.1 |
|
Number x value |
12 u |
0.6 u |
1.3 u |
13.9 u |
Number of $1 coins is the repeated identity.
Make the number of $1 coins the same.
LCM of 3 and 4 = 12
Total number of coins = 28 u
28 u = 280
1 u = 280 ÷ 28 = 10
Total value of coins
= 12 u 0.6 u 1.3 u
= 13.9 u
= 13.9 x 10
= $139
Answer(s): $139