Correct Answer - Option 1 :

20 km/h

**Given: **

Distance = 75 km

Time taken in opposite direction = 1.5 h

Time taken in same direction = 7.5 h

**Formula Used:**

Speed = Distance/Time

**Concept Used:**

If two objects are moving with speeds S_{1} and S_{2}, Their relative speed is

S_{1} + S_{2} in the opposite direction and

S_{1} – S_{2} in the same direction

**Calculation:**

Let the speed of Ankit is S_{1} and speed of Aniket is S_{2}

Relative speed while coming towards each other = S_{1} + S_{2}

Relative speed while going in same direction = S_{1} – S_{2}

Using the speed formula,

S_{1} + S_{2} = 75/1.5 = 50 km/h

S_{1} – S_{2} = 75/7.5 = 10 km/h

Adding both the equations,

2 S_{1 }= 60

⇒ S_{1 }= 30 km/h

⇒ S_{2} = 50 – 30 = 20 km/h

**∴ ****Speed of slower is 20 km/h.**