There were a total of forty-two 10-cent coins and 50-cent coins in a bag. Given that the total amount of money in the bag was $13.80. How many 10-cent coins were there in the bag?
Number of 50-cent coins |
Value of 50-cent coins |
Number of 10-cent coins |
Value of 10-cent coins |
Total value |
42
|
42 x 50 = 2100¢ |
0
|
0
|
2100¢
|
41
|
41 x 50 = 2050¢ |
1
|
1 x 10 = 10¢ |
2060¢
|
24
|
24 x 50 = 1200¢ |
18
|
18 x 10 = 180¢ |
1380¢ |
$1 = 100¢
$13.80 = 1380¢
Amount in the bag if all are 50-cent coins
= 42 x 50
= 2100¢
Big difference between the value of 50-cent coins and 10-cent coins
= 2100 - 1380
= 720¢
Small difference between the value of one 50-cent coin and one 10-cent coin
= 50 - 10
= 40¢
Number of 10-cent coins
= 720 ÷ 40
= 18
Answer(s): 18