Here's the question you clicked on:
Hpbby
A person leaves home at 8:00 a.m. and drives to a destination at a rate of 40 mph. The person returns at a rate of 25 mph and arrives at 2:30 p.m. How far was the destination? 65 miles 100 miles 130 miles
Answer is 100 mile, total travel time is 6 hours and 30 min. At speed of 40 mph you will cover 100 miles in 2.5 hours and at 25 mph it will take 4 hours to cover 100 mile. By adding 4 and 2.5 hours you end up with 6.5 hours or 6 hours 30 min.
LCD in what sense ? LCD can be liquid crystal display but it can be many other things.
Ah :) you are right I should have thought about LCD in math sense.