The average number of pages Fiona read in a certain number of days was 15. In the next seven days, Fiona read another 13 pages. As a result, the average number of pages she read decreased to 11. How many days did Fiona read in total?
| |
At first |
In the end |
| Number |
1 u |
1 u + 7 |
| Value |
15 |
11 |
| Number x value |
15 u |
11 u + 77 |
Number of days that Fiona read at first = 1 u
Number of pages that Fiona read at first
= 1 u x 15
= 15 u
Number of pages that Fiona read in the end = 15 u + 13
Number of days that Fiona read in the end = 1 u + 7
Number of pages that Fiona read in the end
= 11 x (1 u + 7)
= 11 u + 77
15 u + 13 = 11 u + 77
15 u - 11 u = 77 - 13
4 u = 64
1 u = 64 ÷ 4 = 16
Number of days that Fiona read in the end
= 1 u + 7
= 16 + 7
= 23
Answer(s): 23
