There were a total of thirty-four 20-cent coins and 50-cent coins in a bag. Given that the total amount of money in the bag was $12.50. How many 20-cent coins were there in the bag?
Number of 50-cent coins |
Value of 50-cent coins |
Number of 20-cent coins |
Value of 20-cent coins |
Total value |
34
|
34 x 50 = 1700¢ |
0
|
0
|
1700¢
|
33
|
33 x 50 = 1650¢ |
1
|
1 x 20 = 20¢ |
1670¢
|
19
|
19 x 50 = 950¢ |
15
|
15 x 20 = 300¢ |
1250¢ |
$1 = 100¢
$12.50 = 1250¢
Amount in the bag if all are 50-cent coins
= 34 x 50
= 1700¢
Big difference between the value of 50-cent coins and 20-cent coins
= 1700 - 1250
= 450¢
Small difference between the value of one 50-cent coin and one 20-cent coin
= 50 - 20
= 30¢
Number of 20-cent coins
= 450 ÷ 30
= 15
Answer(s): 15