The average number of pages Usha read in a certain number of days was 16. In the next three days, Usha read another 90 pages. As a result, the average number of pages she read increased to 23. How many days did Usha read in total?
| |
At first |
In the end |
| Number |
1 u |
1 u + 3 |
| Value |
16 |
23 |
| Number x value |
16 u |
23 u + 69 |
Number of days that Usha read at first = 1 u
Number of pages that Usha read at first
= 1 u x 16
= 16 u
Number of pages that Usha read in the end = 16 u + 90
Number of days that Usha read in the end = 1 u + 3
Number of pages that Usha read in the end
= 23 x (1 u + 3)
= 23 u + 69
23 u + 69 = 16 u + 90
23 u - 16 u = 90 - 69
7 u = 21
1 u = 21 ÷ 7 = 3
Number of days that Usha read in the end
= 1 u + 3
= 3 + 3
= 6
Answer(s): 6
