Correct Answer - Option 1 : 2 km/hr

**Given:**

Downstream distance = 24 km

Upstream distance = 24 km

**Formula Used:**

Speed = Distance/Time

D = B + S

U = B - S

where, D → Downstream speed, U → Upstream speed, B → Speed of the boat in still water, S → Speed of the stream.

**Calculations:**

24/D + 24/U = 14

⇒ 24/(B + S) + 24/(B - S) = 14

⇒ 24/(7 + S) + 24/(7 - S) = 14

⇒ [24 × (7 - S) + 24 × (7 + S)]/(7 + S) × (7 - S) = 14

⇒ 24 × 7 × 2/(49 - S^{2}) = 14

⇒ 24 = 49 - S^{2}

⇒ S^{2} = 49 - 24 = 25

⇒ S = 5 km/hr

U = (B - S)

⇒ U = (7 - 5)

⇒ U = 2 km/hr

**∴ The upstream speed is 2 km/hr.**