The average number of pages Wendy read in a certain number of days was 15. In the next three days, Wendy read another 85 pages. As a result, the average number of pages she read increased to 23. How many days did Wendy read in total?
| |
At first |
In the end |
| Number |
1 u |
1 u + 3 |
| Value |
15 |
23 |
| Number x value |
15 u |
23 u + 69 |
Number of days that Wendy read at first = 1 u
Number of pages that Wendy read at first
= 1 u x 15
= 15 u
Number of pages that Wendy read in the end = 15 u + 85
Number of days that Wendy read in the end = 1 u + 3
Number of pages that Wendy read in the end
= 23 x (1 u + 3)
= 23 u + 69
23 u + 69 = 15 u + 85
23 u - 15 u = 85 - 69
8 u = 16
1 u = 16 ÷ 8 = 2
Number of days that Wendy read in the end
= 1 u + 3
= 2 + 3
= 5
Answer(s): 5
