The average number of pages Ivory read in a certain number of days was 13. In the next six days, Ivory read another 94 pages. As a result, the average number of pages she read increased to 15. How many days did Ivory read in total?
|
At first |
In the end |
Number |
1 u |
1 u + 6 |
Value |
13 |
15 |
Number x value |
13 u |
15 u + 90 |
Number of days that Ivory read at first = 1 u
Number of pages that Ivory read at first
= 1 u x 13
= 13 u
Number of pages that Ivory read in the end = 13 u + 94
Number of days that Ivory read in the end = 1 u + 6
Number of pages that Ivory read in the end
= 15 x (1 u + 6)
= 15 u + 90
15 u + 90 = 13 u + 94
15 u - 13 u = 94 - 90
2 u = 4
1 u = 4 ÷ 2 = 2
Number of days that Ivory read in the end
= 1 u + 6
= 2 + 6
= 8
Answer(s): 8