MeritTrac Speed, Time and Distance Questions and Answers Quiz-1

Let total distance =D=D
Distance travelled at 4 kmph speed =(2/3)D

Distance travelled at 5 kmph speed =(1−2/3)D=(1/3)D
Total time =1 hr 24 min = (60+24) min =84/60 21/15 hr

We know,

Time=Distance/Speed

Total time

21/15=((2/3)/4)D+((1/3)/5)D
Solving
84=14D

D=6 km

((1/2)x)/21 + ((1/2)x)/24 = 10

Solving this we get
15x = 168 x 20
Further
x = (168 x 20)/15 = 224 km.

Let Speed of the man is x kmph.
Distance covered in 10 minutes at 20 kmph =
distance covered in 8 minutes at (20+x) kmph.
Or, 20*10/60 = 8/60(20+x)
Or, 200 = 160+8x
Or, 8x = 40
Hence, x = 5kmph.

Detailed Explanation:
A _____________M_______________B

Solution here : - https://prepinsta.com/two-busses-mumbai-
leave-delhi-6-6-45-travel-100-kmph-136-kmph-respectively-
many-kilometers-delhi-will-two-trains-together/

Visit the above Page for detailed solution.

Relative speed of A & C will be.. 15 m/s.. hence for first they will meet at
2150/15= 143.33 sec (around 2min 23sec).. so time will be
10:02:23..this case will not be considered as it is before 10:05.
Again they will meet at
4300/15=286.66 sec(around 4min 46sec).. time will be 10:07:10.
this case will be considered
Hence in 7min10 sec i.e 430
In 430sec B will cover 430*8 metres=3440 metres

let they meet after x h after 7 am
distance cover by atul=distance cover bysam
15(x+2)=20x
15x+30=20x
x=6
7am+6 h=1pm
so ans is 1pm

A →_______60Km_________← B
Let the speed of A= x kmph and that of B = y kmph;

According to the question;
X*6+y*6 = 60
Or, x+y = 10 --------- (i)

And,

{(2x/3)*5}+(2y*5) = 60
Or, 10x+30y = 180;
Or, x+3y = 18; ---------- (ii)
From equation (i)*3 - (ii)
3x+3y-x-3y = 30-18
Or, 2x = 12
Hence, x = 6 kmph.

Let length of each train be x meter.
Then, speed of 1st train = x/18 m/sec;
Speed of 2nd train = x/12 m/sec;

Now,
When both trains cross each other, time taken;
= [2x/(x/{18)+(x/12)}]
= 2x/[(2x+3x)/36] = 2x*36/5x
= 72/5
= 14.4 seconds.

Let the speed of the stream be x kmph and both the
boats meet after t hour.

According to the question,
(12+x)*t+(15-x)*t = 108;
Or, 12t+15t = 108;
Or, 27t = 108;
Or, 108/27 = 4 hours.

(6-x) = (8-1.5x)
Or, x = 4cm.
So, It will take 4 hours to burn it in such a way that
they will remain equal in lengths.