SSC CGL 2024 PYQ — Question 63

The correct answer is option 1 i.e. 1 hr 30 min.

The speed of the boat in still water = b km/h

The speed of the current = c km/h

Against the current:
⇒$\frac{2}{b - c} = 1 \quad \Rightarrow \quad b - c = 2 \quad$ (Equation 1)

 Along with the current:
⇒ $\frac{1}{b + c} = \frac{1}{6} \quad \Rightarrow \quad b + c = 6 \quad$( Equation 2)

b = (2 + 6)/2 = 4

c = (6 - 2)/2 = 2

The time to travel 6 km in stationary water is:

= 6/b = 6/4 = 1.5 hours or 1 hour 30 min.