A jar contained $5 and $10 notes with a total value of $420. 6 pieces of $10 were exchanged for $5 notes of similar value. In the end, the number of $5 notes was the same as the $10 notes. How many $5 notes were there at first?
|
$5 |
$10 |
Before |
1 u - 12 |
1 u + 6 |
Change |
+ 12 |
- 6 |
After |
1 u |
1 u |
Total value of $5 and $10 notes remains unchanged after the exchange of notes of similar value.
Total value of 6 pieces of $10-notes
= 6 x 10
= $60
Number of $5-notes that 6 pieces of $10-notes were exchanged for
= 60 ÷ 5
= 12
In the end |
$5 |
$10 |
Total |
Number |
1 u |
1 u |
2 u |
Value |
5 |
10 |
|
Total Value |
5 u |
10 u |
15 u |
Total value of $5 and $10 notes
= 5 u + 10 u
= 15 u
15 u = 420
1 u = 420 ÷ 15 = 28
Number of $5 notes at first
= 1 u - 12
= 28 - 12
= 16
Answer(s): 16