Last Sunday, Ahmad withdrew an equal number of $20-notes and $100-notes from the bank. After spending 28 pieces of $20-notes and 10 pieces of $100-notes, the ratio of the remaining $20-notes to $100-notes became 2 : 5.
- How many $20-notes had he left?
- What was the total value of the notes which Ahmad withdrew from the bank?
|
$20-notes |
$100-notes |
Before |
2 u + 28 |
5 u + 10 |
Change |
- 28 |
- 10 |
After |
2 u |
5 u |
(a)
Ahmad withdrew an equal number of $20-notes and $100-notes from the bank. So, the number of notes of each type is the same.
5 u + 10 = 2 u + 28
5 u - 2 u = 28 - 10
3 u = 18
1 u = 18 ÷ 3 = 6
Number of $20 notes that Ahmad had left
= 2 u
= 2 x 6
= 12
(b)
Number of each type of notes that Ahmad withdrew
= 12 + 28
= 40
Value of one set of $20-note and 100-note
= 20 + 100
= $120
Total value of the notes that Ahmad withdrew
= 120 x 40
= $4800
Answer(s): (a) 12; (b) $4800