There were a total of forty-one 10-cent coins and 20-cent coins in a bag. Given that the total amount of money in the bag was $7.40. How many 10-cent coins were there in the bag?
Number of 20-cent coins |
Value of 20-cent coins |
Number of 10-cent coins |
Value of 10-cent coins |
Total value |
41
|
41 x 20 = 820¢ |
0
|
0
|
820¢
|
40
|
40 x 20 = 800¢ |
1
|
1 x 10 = 10¢ |
810¢
|
33
|
33 x 20 = 660¢ |
8
|
8 x 10 = 80¢ |
740¢ |
$1 = 100¢
$7.40 = 740¢
Amount in the bag if all are 20-cent coins
= 41 x 20
= 820¢
Big difference between the value of 20-cent coins and 10-cent coins
= 820 - 740
= 80¢
Small difference between the value of one 20-cent coin and one 10-cent coin
= 20 - 10
= 10¢
Number of 10-cent coins
= 80 ÷ 10
= 8
Answer(s): 8