The average number of pages Linda read in a certain number of days was 18. In the next four days, Linda read another 37 pages. As a result, the average number of pages she read decreased to 13. How many days did Linda read in total?
| |
At first |
In the end |
| Number |
1 u |
1 u + 4 |
| Value |
18 |
13 |
| Number x value |
18 u |
13 u + 52 |
Number of days that Linda read at first = 1 u
Number of pages that Linda read at first
= 1 u x 18
= 18 u
Number of pages that Linda read in the end = 18 u + 37
Number of days that Linda read in the end = 1 u + 4
Number of pages that Linda read in the end
= 13 x (1 u + 4)
= 13 u + 52
18 u + 37 = 13 u + 52
18 u - 13 u = 52 - 37
5 u = 15
1 u = 15 ÷ 5 = 3
Number of days that Linda read in the end
= 1 u + 4
= 3 + 4
= 7
Answer(s): 7
