Answer:
The total number of pages read by him before study hall is 178 .
Step-by-step explanation:
Given as :
The total number of page read after 20 min = 120 pages
After 45 min of reading , he is on page number 178
Let The total number of pages read by him = n
Now, Since after 45 min of reading he is on page number 178
so, After page number 120, he started reading from page number 121 and read up to page number 178
Or, The number of pages between page number 178 and page number 120 = (178 - 121 ) + 1
Or, The number of pages between page number 178 and page number 120 = 57 + 1
Or, The number of pages between page number 178 and page number 120 = 58
So, The total number of pages he read in all = The total number of page read after 20 min + number of pages he read for 45 min
∴ n = 120 + 58
I.e n = 178
The total number of pages read by him = n = 178
Hence The total number of pages read by him before study hall is 178 . Answer