In order to complete a reading assignment on time, Terry planned to read 100 pages per day. However, she read only 50 pages per day at first, leaving 800 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?  Options.
A) 12 B) 14 C) 16 D) 10 E) 18
D=100*X - according to the plan, assignment to be completed on time reading 100 pages per day for next X days. But, Terry's plans changed so she read as follow:   50 pages for first Y days and 800 pages for last 6 days, we get these equations:   50*Y+800=100*X   X-Y=6 ---------&gt;&gt;X planned number of days, Y - actually used reading 60 pages per day and 6 leftover days used to complete a lump 780 pages   From above we find that X=Y+6 and 50Y+800=100Y+600 or 50Y=200 ---&gt;&gt;&gt;&gt;&gt; Y=4, hence X=10   Answer : 10
<result>D</result>
In order to complete a reading assignment on time, Terry planned to read 100 pages per day. However, she read only 50 pages per day at first, leaving 800 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?