The average number of pages Abi read in a certain number of days was 17. In the next three days, Abi read another 100 pages. As a result, the average number of pages she read increased to 24. How many days did Abi read in total?
| |
At first |
In the end |
| Number |
1 u |
1 u + 3 |
| Value |
17 |
24 |
| Number x value |
17 u |
24 u + 72 |
Number of days that Abi read at first = 1 u
Number of pages that Abi read at first
= 1 u x 17
= 17 u
Number of pages that Abi read in the end = 17 u + 100
Number of days that Abi read in the end = 1 u + 3
Number of pages that Abi read in the end
= 24 x (1 u + 3)
= 24 u + 72
24 u + 72 = 17 u + 100
24 u - 17 u = 100 - 72
7 u = 28
1 u = 28 ÷ 7 = 4
Number of days that Abi read in the end
= 1 u + 3
= 4 + 3
= 7
Answer(s): 7
