A jar contained $10 and $5 notes with a total value of $315. 8 pieces of $5 were exchanged for $10 notes of similar value. In the end, the number of $10 notes was the same as the $5 notes. How many $10 notes were there at first?
|
$10 |
$5 |
Before |
1 u - 4 |
1 u + 8 |
Change |
+ 4 |
- 8 |
After |
1 u |
1 u |
Total value of $10 and $5 notes remains unchanged after the exchange of notes of similar value.
Total value of 8 pieces of $5-notes
= 8 x 5
= $40
Number of $10-notes that 8 pieces of $5-notes were exchanged for
= 40 ÷ 10
= 4
In the end |
$10 |
$5 |
Total |
Number |
1 u |
1 u |
2 u |
Value |
10 |
5 |
|
Total Value |
10 u |
5 u |
15 u |
Total value of $10 and $5 notes
= 10 u + 5 u
= 15 u
15 u = 315
1 u = 315 ÷ 15 = 21
Number of $10 notes at first
= 1 u - 4
= 21 - 4
= 17
Answer(s): 17