The ratio of the number of $10-notes to $20-notes in Ivory's handbag was 1 : 3. Ivory exchanged 14 pieces of $20-notes for $10-notes. She then had an equal number of $10-notes and $20-notes. What was the total value of $10-notes and $20-notes in Ivory's handbag at first?
| |
$10-notes |
$20-notes |
| Before |
1 u |
3 u |
| Change |
+ 28 |
- 14 |
| After |
1 u + 28 |
3 u - 14 |
Value of 14 pieces of $20-notes
= 14 x 20
= $280
Number of $10-notes that Ivory exchanged for
= 280 ÷ 10
= 28
After the exchange, Ivory had an equal number of $10-notes and $20-notes.
3 u - 14 = 1 u + 28
3 u - 1 u = 28 + 14
2 u = 42
1 u = 42 ÷ 2 = 21
Number of $10-notes at first
= 1 u
= 21
Value of $10-notes at first
= 21 x 10
= $210
Number of $20-notes at first
= 3 u
= 3 x 21
= 63
Value of $20-notes at first
= 63 x 20
= $1260
Total value of $10-notes and $20-notes at first
= 210 + 1260
= $1470
Answer(s): $1470
