Two cars are moving in the same direction with the same speed `30 km//hr`. They are separated by a distance of `5 km`, the speed of a car moving in the opposite direction of it meets these two cars at an interval of `4` minutes, will be.

Explanation

Since the two cars (A) and (B) are moving with same velocity, the separation between then will remain the same (=5 km).
Let car (c ) be moving in opposite derection to cars ` A and B`, with velocity ` vec v_c` relative to ground, Then relative velocuty of car ` c` relative to car (A) and (B) wil be
` vec v _(rel) = vec c_C-vec V`
As 1 vec V` is opposite ot ` vec v_C`,
so ` v_(rel) =v_C - (-v)`
` =v_C + v= (v_C + 30 ) km h^(-1)`
Time taken by car (C ) to cross the cars (A) and (B) will be
` t= S/(v_(rel)) or 4/(60) = 5 /(v_C + 30)`
On solving , ` v_C= 45 km h^(-1)`.