Shannon had thrice as many pens as markers. After giving away 70 pens and selling 20 pens, she found out that she had twice as many pens as markers left.
- How many pens did Shannon have at first?
- How many pens and markers did Shannon have altogether at first?
|
Pens |
Markers |
Total |
Before |
3 u |
1 u |
4 u |
Change 1 |
- 70 |
|
- 1 u |
Change 2 |
- 20 |
|
After |
2 u |
1 u |
3 u |
(a)
The number of markers remains unchanged.
Number of pens that Shannon gave away or sold
= 3 u - 2 u
= 1 u
1 u = 70 + 20 = 90
Number of pens that Shannon had at first
= 3 u
= 3 x 90
= 270
(b)
Total number of pens and markers that Shannon had at first
= 1 u + 3 u
= 4 u
= 4 x 90
= 360
Answer(s): (a) 270; (b) 360