The ratio of the number of $2-notes to $10-notes in Hilda's handbag was 1 : 7. Hilda exchanged 4 pieces of $10-notes for $2-notes. She then had an equal number of $2-notes and $10-notes. What was the total value of $2-notes and $10-notes in Hilda's handbag at first?
| |
$2-notes |
$10-notes |
| Before |
1 u |
7 u |
| Change |
+ 20 |
- 4 |
| After |
1 u + 20 |
7 u - 4 |
Value of 4 pieces of $10-notes
= 4 x 10
= $40
Number of $2-notes that Hilda exchanged for
= 40 ÷ 2
= 20
After the exchange, Hilda had an equal number of $2-notes and $10-notes.
7 u - 4 = 1 u + 20
7 u - 1 u = 20 + 4
6 u = 24
1 u = 24 ÷ 6 = 4
Number of $2-notes at first
= 1 u
= 4
Value of $2-notes at first
= 4 x 2
= $8
Number of $10-notes at first
= 7 u
= 7 x 4
= 28
Value of $10-notes at first
= 28 x 10
= $280
Total value of $2-notes and $10-notes at first
= 8 + 280
= $288
Answer(s): $288
