There were a total of forty 20-cent coins and 50-cent coins in a bag. Given that the total amount of money in the bag was $18.50. 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 |
40
|
40 x 50 = 2000¢ |
0
|
0
|
2000¢
|
39
|
39 x 50 = 1950¢ |
1
|
1 x 20 = 20¢ |
1970¢
|
35
|
35 x 50 = 1750¢ |
5
|
5 x 20 = 100¢ |
1850¢ |
$1 = 100¢
$18.50 = 1850¢
Amount in the bag if all are 50-cent coins
= 40 x 50
= 2000¢
Big difference between the value of 50-cent coins and 20-cent coins
= 2000 - 1850
= 150¢
Small difference between the value of one 50-cent coin and one 20-cent coin
= 50 - 20
= 30¢
Number of 20-cent coins
= 150 ÷ 30
= 5
Answer(s): 5