Last Monday, Mark withdrew an equal number of $20-notes and $2-notes from the bank. After spending 31 pieces of $20-notes and 10 pieces of $2-notes, the ratio of the remaining $20-notes to $2-notes became 7 : 10.
- How many $20-notes had he left?
- What was the total value of the notes which Mark withdrew from the bank?
| |
$20-notes |
$2-notes |
| Before |
7 u + 31 |
10 u + 10 |
| Change |
- 31 |
- 10 |
| After |
7 u |
10 u |
(a)
Mark withdrew an equal number of $20-notes and $2-notes from the bank. So, the number of notes of each type is the same.
10 u + 10 = 7 u + 31
10 u - 7 u = 31 - 10
3 u = 21
1 u = 21 ÷ 3 = 7
Number of $20 notes that Mark had left
= 7 u
= 7 x 7
= 49
(b)
Number of each type of notes that Mark withdrew
= 49 + 31
= 80
Value of one set of $20-note and 2-note
= 20 + 2
= $22
Total value of the notes that Mark withdrew
= 22 x 80
= $1760
Answer(s): (a) 49; (b) $1760
