Two boys A and B start at the same time to ride from Delhi to Meerut, 60 km away. A rides 4 km/h slower than B. B reaches Meerut and at once turns back meeting A at a place 12 km from Meerut. Find the speed of A.

8 km/h

Let speed of B = s km/hr

Speed of A = ( s - 4 ) km/hr

Distance traveled by B = ( 60 + 12 ) km/hr = 72 km/hr

Distance traveled by A = ( 60 - 12 ) km/hr = 48 km/hr

We know that ,

Time = \(\frac{Distance }{Speed}\)

According to question ,

\(\frac{48 }{( s - 4 )}\) = \(\frac{72 }{s }\) 

48 s = 72 s - 288

24s = 288

s = 12

Speed of A = ( s - 4 )

= ( 12 - 4 )

= 8 km/hr