There were a total of thirty-nine 10-cent coins and 50-cent coins in a bag. Given that the total amount of money in the bag was $13.10. 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 |
39
|
39 x 50 = 1950¢ |
0
|
0
|
1950¢
|
38
|
38 x 50 = 1900¢ |
1
|
1 x 10 = 10¢ |
1910¢
|
23
|
23 x 50 = 1150¢ |
16
|
16 x 10 = 160¢ |
1310¢ |
$1 = 100¢
$13.10 = 1310¢
Amount in the bag if all are 50-cent coins
= 39 x 50
= 1950¢
Big difference between the value of 50-cent coins and 10-cent coins
= 1950 - 1310
= 640¢
Small difference between the value of one 50-cent coin and one 10-cent coin
= 50 - 10
= 40¢
Number of 10-cent coins
= 640 ÷ 40
= 16
Answer(s): 16