John and Sarah are collecting data on the number of pages in books they read over the summer. The table below shows the number of pages for six books read by each.
Each column shows pages read
| 1 | 2 | 3 | 4 | 5 | 6 | |
|---|---|---|---|---|---|---|
| John | 180 | 220 | 150 | 195 | 210 | 175 |
| Sarah | x | 190 | 205 | 185 | 215 | 170 |
The mean number of pages in the books Sarah read is pages less than the mean number of pages in the books John read. What is the value of ?
