In order to complete a reading assignment on time, Terry planned to read 100 pages per day. However, she read only 75 pages per day at first, leaving 625 pages to be read during the last 6 days before the assignment was to be completed. How many days in all did Terry have to complete the assignment on time?	Choose the correct choice from the following options:
A) 8
B) 7
C) 9
D) 10
E) 11
D=100*X - according to the plan, assignment to be completed on time reading 100 pages per day for next X days. 7ut, Terry's plans changed so she read as follow:   75 pages for first Y days and 625 pages for last 6 days, we get these equations:   75*Y+625=100*X   X-Y=6 ---------&gt;&gt;X planned number of days, Y - actually used reading 75 pages per day and 6 leftover days used to complete a lump 625 pages   From above we find that X=Y+6 and 75Y+625=100Y+600 or 25Y=25 ---&gt;&gt;&gt;&gt;&gt; Y=1, hence X=7   Answer : 7
<result>B</result>
In order to complete a reading assignment on time, Terry planned to read 100 pages per day. However, she read only 75 pages per day at first, leaving 625 pages to be read during the last 6 days before the assignment was to be completed. How many days in all did Terry have to complete the assignment on time?