1
Q:

A son and father goes for boating in river upstream . After rowing for 1 mile son notices the hat of his father falling in the river. After 5 min he tells his father that his hat has fallen. So they turn round and are able to pick the hat at the point from where they began boating after 5min. Find the speed of river  in miles/hours ?

A) 4 mile/hr B) 6 mile/hr
C) 2 mile/hr D) 5 mile/hr

Answer:   B) 6 mile/hr



Explanation:

Let the speed of river and boat be 'r' m/min and 'b' m/min.
so relative speed in upstream (b-r)m/min and in downstream (b+r)m/min.
Now in upstream distnce covered in 5 min is 5(b-r)miles
so total distnce covered => 1 + 5(b-r)miles in upstream
In downstream distance covered in 5min is 5(b+r)miles
Now 1 + 5(b-r) = 5(b+r)
1+5b-5r = 5b+5r
1 = 10r
r = 1/10 mile/min => 6 mile/hr.

Q:

Kamal consistently runs 240 meters a day and on Saturday he runs for 400 meters. How many kilometers will he have to run in four weeks ?

A) 5.75 kms B) 7.36 kms
C) 8.2 kms D) 6.98 kms
 
Answer & Explanation Answer: B) 7.36 kms

Explanation:

Total running distance in four weeks = (24 x 240) + (4 x 400)

= 5760 + 1600

= 7360 meters

= 7360/1000

=> 7.36 kms

Report Error

View Answer Workspace Report Error Discuss

2 30
Q:

K and L starts walking towards each other at 4 pm at speed of 3 km/hr and 4 km/hr respectively. They were initially 17.5 km apart. At what time do they meet ?

A) 6:00 am B) 6:30 pm
C) 5:45 am D) 5:52 pm
 
Answer & Explanation Answer: B) 6:30 pm

Explanation:

Suppose they meet after 'h' hours

Then

3h + 4h = 17.5

7h = 17.5

h = 2.5 hours

So they meet at => 4 + 2.5 = 6:30 pm

Report Error

View Answer Workspace Report Error Discuss

9 164
Q:

P, Q and R start simultaneously from A to B. P reaches B, turns back and meet Q at a distance of 11 km from B. Q reached B, turns back and meet R at a distance of 9 km from B. If the ratio of the speeds of P and R is 3:2, what is the distance between A and B ?

A) 99 B) 100
C) 89 D) 1
 
Answer & Explanation Answer: A) 99

Explanation:

Let, Distance between A and B = d

Distance travelled by P while it meets Q = d + 11

Distance travelled by Q while it meets P = d – 11

Distance travelled by Q while it meets R = d + 9

Distance travelled by R while it meets Q = d – 9

Here the ratio of speeds of P & Q => SP : SQ = d + 11 : d – 11

The ratio of speeds of Q & R => SQ : SR = d + 9 : d – 9

But given Ratio of speeds of P & R => P : R = 3 : 2

=> 

=>  d = 1, 99

=> d = 99 satisfies.

Therefore, Distance between A and B = 99

Report Error

View Answer Workspace Report Error Discuss

6 90
Q:

A man can row 8 kmh in still water. If the river is running at 2 kmh, it takes 4 hrs more upstream than to go downstream for the same distance. Then the distance is given by

A) 54 kms B) 32 kms
C) 45 kms D) 60 kms
 
Answer & Explanation Answer: D) 60 kms

Explanation:

Let the distance be d.

=> 2d = 120 

=> d = 60 kms.

Report Error

View Answer Workspace Report Error Discuss

5 306
Q:

In what time a 360 m. long train moving at the speed of 44 km/hr will cross a 140 m. long bridge ?

A) 36 sec B) 39 sec
C) 41 sec D) 43 sec
 
Answer & Explanation Answer: C) 41 sec

Explanation:

Speed = 44 kmph x 5/18 = 110/9 m/s

We know that, Time = distance/speed

Time = (360 + 140) / (110/9)

= 500 x 9/110 = 41 sec.

Report Error

View Answer Workspace Report Error Discuss

6 155