A jar contained $10 and $2 notes with a total value of $120. 5 pieces of $2 were exchanged for $10 notes of similar value. In the end, the number of $10 notes was the same as the $2 notes. How many $10 notes were there at first?
|
$10 |
$2 |
Before |
1 u - 1 |
1 u + 5 |
Change |
+ 1 |
- 5 |
After |
1 u |
1 u |
Total value of $10 and $2 notes remains unchanged after the exchange of notes of similar value.
Total value of 5 pieces of $2-notes
= 5 x 2
= $10
Number of $10-notes that 5 pieces of $2-notes were exchanged for
= 10 ÷ 10
= 1
In the end |
$10 |
$2 |
Total |
Number |
1 u |
1 u |
2 u |
Value |
10 |
2 |
|
Total Value |
10 u |
2 u |
12 u |
Total value of $10 and $2 notes
= 10 u + 2 u
= 12 u
12 u = 120
1 u = 120 ÷ 12 = 10
Number of $10 notes at first
= 1 u - 1
= 10 - 1
= 9
Answer(s): 9