Question

two cars start from one point and and move along two roads at right angles to each other. Their speeds are 36km/hr and 48km/hr respectively.After 15 seconds the distance between them will be
A.400m
B.150m
C.300m
D.250m​

Answer 1

After 15 seconds the distance between the two cars is 250 m.

Step-by-step explanation:

Speed of car 1 = 36 km/hr. = 36 ×5/18 m/s =10m/s

Distance covered in 15 seconds = Speed x Time  

   = 10 m/s x 15 s = 150 m

Speed of car 2 = 48 km/hr. = 48 ×5/18 m/s =40/3m/s

Distance covered in 15 seconds = Speed x Time  

   = 40/3 m/s x 15 s = 200 m

Since, the 2 cars have started form a point and is moving at right angle to each other,

Hence, the distance between them = Hypotenuse of a right angled triangle.

Using Pythagoras Theorem,  

Distance between them

= √[(200)^2 + (150)^2]

= √[22500 + 40000] = √62500 = 250

The distance between the two cars is 250 m