Question

A boat can travel 27 km in one hour in still water and travels the same distance against the stream in 90 minutes. How much time will the boat take to travel 90km in the direction of stream?

• A. 4 hours
• B. 4.25 hours
• C. 2.5 hours
• D. 3.5 hours

Answer 1

Answer:

C. 2.5 hours

$$Let ‘s’ be the speed of the boat and ‘w’ be the speed of the stream. </span></p><p style="color: rgb(0,0,0); margin-top: 2px; margin-bottom: 2px" data-pxy="true"><span style="color: rgb(0,0,0); font-family: Verdana, Geneva, sans-serif; font-size: 14px">$$We have, s = 27 km/hr and$\frac{27}{s-w}=1.5hours$

So s-w=18

$w=27-18=9kmph$

We get,$\frac{90}{18+9}=2.5hours$

Hence option C is Right answer.