The average number of pages Pamela read in a certain number of days was 13. In the next four days, Pamela read another 84 pages. As a result, the average number of pages she read increased to 15. How many days did Pamela read in total?
| |
At first |
In the end |
| Number |
1 u |
1 u + 4 |
| Value |
13 |
15 |
| Number x value |
13 u |
15 u + 60 |
Number of days that Pamela read at first = 1 u
Number of pages that Pamela read at first
= 1 u x 13
= 13 u
Number of pages that Pamela read in the end = 13 u + 84
Number of days that Pamela read in the end = 1 u + 4
Number of pages that Pamela read in the end
= 15 x (1 u + 4)
= 15 u + 60
15 u + 60 = 13 u + 84
15 u - 13 u = 84 - 60
2 u = 24
1 u = 24 ÷ 2 = 12
Number of days that Pamela read in the end
= 1 u + 4
= 12 + 4
= 16
Answer(s): 16
