50
Q:

The speed of a car increases by 2 kms after every one hour. If the distance travelling in the first one hour was 35 kms. what was the total distance travelled in 12 hours?

A) 456 kms B) 482 kms
C) 552 kms D) 556 kms

Answer:   C) 552 kms



Explanation:

Total distance travelled in 12 hours    =(35+37+39+.....upto 12 terms)
This is an A.P with first term, a=35, number of terms,
n= 12,d=2.
Required distance    = 12/2[2 x 35+{12-1) x 2]
=6(70+23)
= 552 kms.

Q:

A person can row 8 1/2 km an hour in still water and he finds that it takes him twice as long to row up as to row down the river. The speed of the stream ?

A) 1.78 kmph B) 2.35 kmph
C) 2.83 kmph D) 3.15 kmph
 
Answer & Explanation Answer: C) 2.83 kmph

Explanation:

Given speed of the person = 8 1/2 = 17/2 kmph
Let the speed of the stream = x kmph
speed of upstream = 17/2 - x
speed of downstream = 17/2 + x
But given that,
2(17/2 - x) = 17/2 + x
=> 3x = 17/2
=> x = 2.83 kmph.

Report Error

View Answer Workspace Report Error Discuss

4 48
Q:

Karthik could cover a distance of 200 km in 22 days while resting for 2 hrs. per day. In how many days (approx) he will cover a distance of 250 km while resting for 2 hrs. per day and moving with 2/3rd of the previous speed ?

A) 41.25 days B) 37.5 days
C) 39.75 days D) 40 days
 
Answer & Explanation Answer: A) 41.25 days

Explanation:

Given Karthik can cover the distance of 200 kms resting 2 hrs per day in 22 days.

Let the initial speed be '1'

Hence, Time = 22(24hrs - 2)

Noe new speed = 2/3

Let the number of days he take be 'D'

Therefore, 

D = 11 x 3 x 5/4 = 41.25 days. = 41 1/4 days.

Report Error

View Answer Workspace Report Error Discuss

7 100
Q:

A bus covers its journey at the speed of 80km/hr in 10hours. If the same distance is to be covered in 4 hours, by how much the speed of bus will have to increase ?

A) 85 km/hr B) 95 km/hr
C) 105 km/hr D) 120 km/hr
 
Answer & Explanation Answer: D) 120 km/hr

Explanation:

Initial speed = 80km/hr
Total distance = 80 x 10 = 800km
New speed = 800/4 =200km/hr
Increase in speed = 200 - 80 = 120km/hr

Report Error

View Answer Workspace Report Error Discuss

6 166
Q:

Joel travels the first 3 hours of his journey at 60 mph speed and the remaining 5 hours at 24 mph speed. What is the average speed of Joel's travel in kmph ?

A) 38 kmph B) 40 kmph
C) 60 kmph D) 54 kmph
 
Answer & Explanation Answer: C) 60 kmph

Explanation:

Average speed = Total distance / Total time.

Total distance traveled by Joel = Distance covered in the first 3 hours + Distance covered in the next 5 hours.

Distance covered in the first 3 hours = 3 x 60 = 180 miles
Distance covered in the next 5 hours = 5 x 24 = 120 miles

Therefore, total distance traveled = 180 + 120 = 300 miles.

Total time taken = 3 + 5 = 8 hours.

Average speed = 300/8 = 37.5 mph.

we know that 1 mile = 1.6 kms

=> 37.5 miles = 37.5 x 1.6 = 60 kms

Average speed in Kmph = 60 kmph.

Report Error

View Answer Workspace Report Error Discuss

2 154
Q:

Two persons start running simultaneously around a circular track of length 600 m from the same point at speeds of 25 kmph and 35 kmph. When will they meet for the first time any where on the track  ?

A) 54 sec B) 36 sec
C) 72 sec D) 11 sec
 
Answer & Explanation Answer: B) 36 sec

Explanation:

Time taken to meet the first time = length of track/relative speed

Given the length of the track is 600 m

The relative speed = 25 + 35 = 60 kmph = 60 x 5/18 m

Therefore Time =   = 600/60 x (18/5) = 36 sec.

Report Error

View Answer Workspace Report Error Discuss

2 156