The average number of pages Opal read in a certain number of days was 20. In the next six days, Opal read another 12 pages. As a result, the average number of pages she read decreased to 17. How many days did Opal read in total?
|
At first |
In the end |
Number |
1 u |
1 u + 6 |
Value |
20 |
17 |
Number x value |
20 u |
17 u + 102 |
Number of days that Opal read at first = 1 u
Number of pages that Opal read at first
= 1 u x 20
= 20 u
Number of pages that Opal read in the end = 20 u + 12
Number of days that Opal read in the end = 1 u + 6
Number of pages that Opal read in the end
= 17 x (1 u + 6)
= 17 u + 102
20 u + 12 = 17 u + 102
20 u - 17 u = 102 - 12
3 u = 90
1 u = 90 ÷ 3 = 30
Number of days that Opal read in the end
= 1 u + 6
= 30 + 6
= 36
Answer(s): 36