Correct Answer - Option 4 : 34

**Given:**

Time to travel 33 km upstream = 5.5 hours

Ratio of the speed of the boat to the speed of the stream = 8 ∶ 5

**Formula used:**

Speed = Distance/Time

Downstream speed = u + v

Upstream speed = u – v

u and v are boat and stream speeds

**Calculation:**

Let the speed of the boat to the speed of the stream be 8x and 5x respectively

Upstream speed = 33/5.5 km/hr

⇒ 6 km/hr

Now,

⇒ 8x – 5x = 6

⇒ 3x = 6

⇒ x = 2

Boat speed = 8x = 16 km/hr

Stream speed = 5x = 10 km/hr

New boat speed = 16 × (100 + 50)% = 24 km/hr

Downstream speed = 24 + 10 = 34 km/hr

**∴ The downstream speed is 34 km/hr**