The average number of pages Marion read in a certain number of days was 18. In the next eight days, Marion read another 18 pages. As a result, the average number of pages she read decreased to 16. How many days did Marion read in total?
| |
At first |
In the end |
| Number |
1 u |
1 u + 8 |
| Value |
18 |
16 |
| Number x value |
18 u |
16 u + 128 |
Number of days that Marion read at first = 1 u
Number of pages that Marion read at first
= 1 u x 18
= 18 u
Number of pages that Marion read in the end = 18 u + 18
Number of days that Marion read in the end = 1 u + 8
Number of pages that Marion read in the end
= 16 x (1 u + 8)
= 16 u + 128
18 u + 18 = 16 u + 128
18 u - 16 u = 128 - 18
2 u = 110
1 u = 110 ÷ 2 = 55
Number of days that Marion read in the end
= 1 u + 8
= 55 + 8
= 63
Answer(s): 63
