The number of 10-cent coins in a box is as many as the number of $1-dollar coins. The total value of the coins is $42.90.
- Find the total number of coins in the box.
- Find the total value of 10-cent coins in the box.
|
10-cent |
$1-dollar |
Total |
Number |
1 u |
1 u |
2 u |
Value |
0.10 |
1 |
|
Total value |
0.1 u |
1 u |
1.1 u |
(a)
Total value of 10-cent and $1 coins
= 0.10 x 1 u + 1 x 1 u
= 0.1 u + 1 u
= 1.1 u
1.1 u = 42.90
1 u = 42.90 ÷ 1.1 = 39
Total number of coins
= 2 u
= 2 x 39
= 78
(b)
Total value of 10-cent coins
= 39 x 0.10
= $3.90
Answer(s): (a) 78; (b) $3.90