aptitude round

A man rows ‘k’ km upstream and back again downstream to the same point in H hours. The speed of rowing in still water is s km/hr and the rate of stream is r km/hr. Then

• (s^2-r^2) =2sk /H

• (r + s) = k.H / (r -s)

• rs = kH

• none of the above

The captain of a cricket team of 11 members is 26 years old and the wicket keeper is 3

years older. If the ages of these two are excluded, the average age of the remaining

players is one year less than the average age of the whole team. What is the average

age of the team?

• 23

• 24

• 25

• none of these

Two trains running in opposite directions cross a man standing on the platform in 27 seconds and 17 seconds respectively and they cross each other in 23 seconds. The ratio of their speeds is:

• 1:3

• 3:2

• 3:4

• none of these

A farmer travelled a distance of 61 km in 9 hours. He travelled partly on foot @ 4 km/hr and partly on bicycle @ 9 km/hr. The distance travelled on foot is:

• 14km

• 15km

• 16km

• 17km

The cost price of 20 articles is the same as the selling price of x articles. If the profit is 25%, then the value of x is:

• 15

• 25

• 18

• 16

What is the speed of the train whose length Is 210 metres?

I. The train crosses another train (Howrah Express/12869) of 300 metres length running in opposite direction in 10 seconds.

II. The train crosses another train (Howrah Express/12869) running in the same direction at the speed of 60 km/hr in 30 seconds

• I alone sufficient while II alone not sufficient to answer

• II alone sufficient while I alone not sufficient to answer

• Either l or II alone sufficient to answer

• Both I and II are necessary to answer

A motorboat can travel at 5 km/hr in still water. It travelled 90 km downstream in a river and then returned, taking altogether 100 hours. Find the rate of flow of the river.

• 3 km/hr

• 3.5 km/hr

• 2 km/hr

• 4 km/hr

A father said to his son, "I was as old as you are at the present at the time of your

birth". If the father's age is 38 years now, the son's age five years back was

• 19

• 14

• 33

• 38

train passes a station platform in 36 seconds and a man standing on the platform in 20 seconds. If the speed of the train is 54 km/hr, what is the length of the platform?

• 120m

• 240m

• 300m

• 260m

The average of 20 numbers is zero. Of them, at the most, how many may be greater

than zero?

• 0

• 1

• 19

• 20