Joelle and Kathy had an equal number of pens at first. Joelle used
13 of her pens and Kathy used
19 of her pens. They used 40 pens altogether. How many pens did Kathy have in the end?
| |
Joelle |
Kathy |
| Before |
3x3 =
9 u |
9x1 =
9 u |
| Change |
- 1x3 =
- 3 u |
- 1x1 =
- 1 u |
| After |
2x3 =
6 u |
8x1 =
8 u |
The number of pens that Joelle and Kathy each had at first is the same. Make the number of pens that Joelle and Kathy each had at first the same. LCM of 3 and 9 is 9.
Number of pens that Joelle and Kathy used
= 3 u + 1 u
= 4 u
4 u = 40
1 u = 40 ÷ 4 = 10
Number of pens that Kathy had in the end
= 8 u
= 8 x 10
= 80
Answer(s): 80
