Correct Answer - Option 1 : 2 hours

**Given:**

Distance covered in 4 hours in upstream = 28 km

Distance covered in 2 hours in downstream = 50 km

**Formula used:**

Speed of an object in downstream = x + y

Speed of an object in upstream = x – y

Speed of object in still water, x = (D + U)/2

Speed of stream, y = (D - U)/2

where,

D = Speed of object in downstream

U = Speed of object in upstream

**Calculation:**

Speed of object in upstream = 28/4

⇒ 7 km/h

Speed of object in downstream = 50/2

⇒ 25 km/h

Speed of object in still water, x = (D + U)/2

⇒ x = (7 + 25)/2

⇒ 16 km/h

Time taken to cover 32 km in still water

⇒ 32/16

⇒ 2 hours

**∴ Ujjwal will take 2 hours to cover 32 km in still water.**