Question No. 10DIRECTIONS for questions 10 to 14: Select the correct alternative from the given choices.A boat started from a point in a river and traveled a certain distance upstream, after which it turned back and returned to its starting point. If the boat covered the round-trip journey in two hours and the net speed of the boat upstream was 25% of that downstream, how much more time (in minutes) did the boat take to travel upstream than what it took to travel downstream?48546072

The question is asking for the difference in time taken by the boat to travel upstream and downstream.

Let's denote:

• the speed of the boat in still water as 'b' (km/h),
• the speed of the river as 'r' (km/h),
• the distance travelled in one direction as 'd' (km),
• the time taken to travel upstream as 't1' (h),
• the time taken to travel downstream as 't2' (h).

The speed of the boat upstream (against the current) is (b-r) km/h, and downstream (with the current) is (b+r) km/h.

According to the problem, the speed of the boat upstream is 25% of that downstream. So, we can write this as: b - r = 0.25 * (b + r) Solving this equation for 'b', we get: b = 5r/3

The total time for the round trip is 2 hours. So, we can write this as: t1 + t2 = 2 Substituting the time 't' as distance over speed, we get: d / (b - r) + d / (b + r) = 2 Substituting 'b' from the previous equation, we get: d / (5r/3 - r) + d / (5r/3 + r) = 2 Solving this equation for 'd', we get: d = 2r

Now, we can find the time taken to travel upstream and downstream: t1 = d / (b - r) = 2r / (5r/3 - r) = 1.2 hours t2 = d / (b + r) = 2r / (5r/3 + r) = 0.8 hours

The difference in time taken to travel upstream and downstream is: t1 - t2 = 1.2 - 0.8 = 0.4 hours

Converting this to minutes, we get: 0.4 * 60 = 24 minutes

So, the boat took 24 minutes more to travel upstream than what it took to travel downstream.