Last week, Reggie had a total of 16 black and grey notebooks. Two weeks later, he sold
23 of all the black notebooks and bought another 24 grey notebooks. Now he has the same number of black and grey notebooks. How many notebooks does he have in the end?
| |
Black |
Grey |
Total |
| Before |
3 u |
1 u - 24 |
4 u - 24 |
| Change |
- 2 u |
+ 24 |
|
| After |
1 u |
1 u |
|
Comparing the black
and grey notebooks in the end |
1 |
1 |
|
Total number of notebooks at first
= 3 u + 1 u - 24
= 4 u - 24
4 u - 24 = 16
4 u = 16 + 24
4 u = 40
1 u = 40 ÷ 4 = 10
Number of notebooks that he has in the end
= 1 u + 1 u
= 2 u
= 2 x 10
= 20
Answer(s): 20
