There were a total of thirty-eight 10-cent coins and 50-cent coins in a bag. Given that the total amount of money in the bag was $15.40. 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 |
38
|
38 x 50 = 1900¢ |
0
|
0
|
1900¢
|
37
|
37 x 50 = 1850¢ |
1
|
1 x 10 = 10¢ |
1860¢
|
29
|
29 x 50 = 1450¢ |
9
|
9 x 10 = 90¢ |
1540¢ |
$1 = 100¢
$15.40 = 1540¢
Amount in the bag if all are 50-cent coins
= 38 x 50
= 1900¢
Big difference between the value of 50-cent coins and 10-cent coins
= 1900 - 1540
= 360¢
Small difference between the value of one 50-cent coin and one 10-cent coin
= 50 - 10
= 40¢
Number of 10-cent coins
= 360 ÷ 40
= 9
Answer(s): 9