00:01
It says that, this question says that one train goes west at the rate of 10 miles per hour.
00:07
So west is over here.
00:09
And another train goes north.
00:10
North is over here at the rate of 20 miles per hour.
00:13
So the train started at the same place.
00:15
So how fast is the distance between them increasing after 30 minutes? so let's say they move for 10 minutes.
00:22
So in 10 minutes, the west one moved from, i'm sorry, they moved from, they moved for t hours, not t minutes.
00:30
So in trs, the distance which the train going to the lift has covered 10t because the distance is speed times time.
00:37
So that's 10t.
00:39
And likewise, the north has covered 20t.
00:42
And the distance between them is this distance, which is the hypotenuse of this particular triangle...