DXC Quants Problems on Trains Quiz 3

Answer: D
Explanation:
Average speed = 2ab/a+b = (2x8x10)/10 = 16 kmph.
Time taken = 4 hours both ways.
So, the two way distance = 16 x 4 miles = 64 km
Hence, the distance one-way = 32 km

Answer: A
Explanation:
Let the time in which he traveled with Rohit = x hr
Then the time in which he traveled with Charlie Puth = (9−x) hr
distance = speed × time
⇒ 4x + 9 (9−x) = 61
⇒ 4x + 81 − 9x = 61
⇒ 5x = 30
⇒ x = 6

Answer: C
Explanation:
Speed of the train = Distance/time
= 416/8 = 52 kmph
Now, speed of car = (speed of truck + 18) kmph
= (52 + 18) = 70 kmph
Distance traveled by car = 416 + 39 = 455 km
Time taken by car = Distance/Speed
= 455/65 = 7 hours

Answer: B
Explanation:
Total distance traveled in 10 hours =(25+27+29+.....upto 10 terms)
This is an A.P with first term, a = 25
number of terms,n= 10.
Common difference, d = 2
Required distance = 10/2[2 x 25+(10-1) x 2]
=5(50+18)
= 340 kms

Answer: A
Explanation:
The time taken by the Rohan = 320/64 = 5 hours
Another man start from Patna by car after 2.5 hour the car starts = 5 - 3 = 2
and the man on can reaches half and hour late which is = 2 + .5 = 2.5
Thus, the ratio between motorcycle to car is 2.5 : 5
or, 1:2

Answer: B
Explanation:
Let the length of the train be X m.

We know that Speed = Distance / Time.
Thus, (X + 150)/15 = 72 x 5/18
or, (X + 150)/15 = 20
or, (X + 150) = 300
=> X = 150

Answer: B
Explanation:
Time taken by Charlie Puth= 3 hrs
Time taken by Selena Gomez =4.5 hrs
The product of time taken by both is the distance
∴ Distance =13.5 km
Charlie Puth covers half the distance in 1 hr (i.e at 8 am) the rest 6.75 km will be covered by Charlie bPuth and Selena Gomez both.
Time taken by them to cover 6.75km = 54 mins
∴ they cross each other at 6: 54 am

Answer: B
Explanation:
In the same time, the train M covers = 210 km
the train N covers= total distance − the distance covered by the first Bus N ⇒ 340−210 =130 km
∴the ratio of their speeds=210 : 130 ⇒ 21 : 13

Answer: D
Explanation:
Downstream speed = 28 +16 = 44 km/h
time taken to travel 44km
Downstream is=88/44 hrs = 2 hours = 120 mins

Answer: D
Explanation:
Distance from M and N be ‘d’
Average Speed = total distance / total time
Average Speed = (d+d) / [(d/60) + (d/90)]= (2d) / [5d/180) =72 km/h

We know that the angle traced by the hour hand in one hour is 30º.
The total angle traced by the hour hand in 17 hours (2 a.m to 7 p.m) is 30 x 17 = 510º.