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Two cars X and Y starts from two places A and B respectively which are 700 km apart at 9 am. Both the cars run at an average speed of 60 km/h, Car X stops at 10 am and again starts at 11 am, while the other car Y continues to run without stopping. When do the two cars cross each other ?
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- 2 : 40 pm
- 3 : 20 pm
- 4 : 10 pm
- 4 : 20 pm
Correct Option: B
Since, the speed of X and Y are 60 km/h each. The distance between A and B is 700 km. Distance traveled by X upto 11 am is 60 km. Since, X stops at 10 am and distance traveled by up to 11 am is 120 km.
Now, the distance between them = 700 - 180 = 520 km
Now, let they will meet at a distance of x km from X's position.
∴ Distance traveled by X = x km
and distance traveled by Y = (520 - x) km
∴ x/60 = (520 - x)/60
⇒ 2x = 520
⇒ x = 260
∴ T = 260/60 = 41/3 h
Thus, they will cross each other after, 41/3 h after 11 am i.e., at 3 : 20 pm.
