Last Tuesday, Riordan withdrew an equal number of $2-notes and $10-notes from the bank. After spending 32 pieces of $2-notes and 16 pieces of $10-notes, the ratio of the remaining $2-notes to $10-notes became 5 : 7.
- How many $2-notes had he left?
- What was the total value of the notes which Riordan withdrew from the bank?
| |
$2-notes |
$10-notes |
| Before |
5 u + 32 |
7 u + 16 |
| Change |
- 32 |
- 16 |
| After |
5 u |
7 u |
(a)
Riordan withdrew an equal number of $2-notes and $10-notes from the bank. So, the number of notes of each type is the same.
7 u + 16 = 5 u + 32
7 u - 5 u = 32 - 16
2 u = 16
1 u = 16 ÷ 2 = 8
Number of $2 notes that Riordan had left
= 5 u
= 5 x 8
= 40
(b)
Number of each type of notes that Riordan withdrew
= 40 + 32
= 72
Value of one set of $2-note and 10-note
= 2 + 10
= $12
Total value of the notes that Riordan withdrew
= 12 x 72
= $864
Answer(s): (a) 40; (b) $864
