Last Tuesday, Andy withdrew an equal number of $20-notes and $10-notes from the bank. After spending 100 pieces of $20-notes and 23 pieces of $10-notes, the ratio of the remaining $20-notes to $10-notes became 3 : 10.
- How many $20-notes had he left?
- What was the total value of the notes which Andy withdrew from the bank?
| |
$20-notes |
$10-notes |
| Before |
3 u + 100 |
10 u + 23 |
| Change |
- 100 |
- 23 |
| After |
3 u |
10 u |
(a)
Andy withdrew an equal number of $20-notes and $10-notes from the bank. So, the number of notes of each type is the same.
10 u + 23 = 3 u + 100
10 u - 3 u = 100 - 23
7 u = 77
1 u = 77 ÷ 7 = 11
Number of $20 notes that Andy had left
= 3 u
= 3 x 11
= 33
(b)
Number of each type of notes that Andy withdrew
= 33 + 100
= 133
Value of one set of $20-note and 10-note
= 20 + 10
= $30
Total value of the notes that Andy withdrew
= 30 x 133
= $3990
Answer(s): (a) 33; (b) $3990
