CAT4MBA

1) Anil calculated that it will take 45 mins. to cover a distance of 60 km by his car.How long will it take to cover the same distance if the speed of his car is reduced by 15km/hr.
a) 36 min.  b)60 mins.  c) 48 mins. d)40 mins.

i think option r not right because i am getting 55.xx minute

2) On a river Q is the mid point  between two points P and R on the same bank of the river .A boat can go from P to Q and back in 12 hours and from P to R in 16 hours.How long would it take to go from R to P?
a) 3(1/3) Hrs.  b) 5 Hrs.  c) 6(2/3) Hrs.  d) None of these.

ans is (d)

3) Two train are running on the line in the same direction at the speed of 50 km /hr. and 30 km/hr. Given that the faster train crosses a man in the slower train in 18 seconds.What is the length of the faster train?
a) 170 m   b) 100 m  c) 98 m  d) 85 m

ans is 100 m

4) Shreya travelled the 1st half of the distance from her house to school at a speed of 10 km/hr. and for exactly half of the remaining time she travelled at 15 km/hr. and rest of the time at 20km/hr. find her average speed.
a) 13km/h  b) 12(8/11)  c) 15km/h.  d) None of these.

ans around(b) but exact value 243/19

5 but if we ) A can beat B by 5 m in 100 m race and B can beat C by 10 m in 200 m race. Then in a race of 400 m,A can beat C by-
a)40 m b) 39m  c) 15m  d) 10 m

ans is 39 m

Little STar

A can give start of 20 m to B in a race of 200m

=> On a stipulated time A can move 200m and B 180m

=> Speed of A / Speed of B = 20 : 18

Similarly, Speed of B/Speed of C = 20 : 19

And thus speed of A / Speed of C = 20/18 * 20/19 = 400/342

So A can beat C by a distance of 400 – 342 = 58m in a 400m race , or

A can beat C by a distance 58/2 = 29 m in a 200m race , or
 

Hi, plz give the solution also...the correct option can b found ...but i want d solution...

1) Anil calculated that it will take 45 mins. to cover a distance of 60 km by his car.How long will it take to cover the same distance if the speed of his car is reduced by 15km/hr.
a) 36 min.  b)60 mins.  c) 48 mins. d)40 mins.

Soln. 45mints or in 3/4 hr. dt person goes 60 km.
       =>speed was=80 km./hr
       After reducin d speed =65km/hr
       to covr 60km. dist it wud take=60/65 x 60 mints=55 mints(approx)
  
OPTION IS NT DR...
For selectin i thnk (b) is nearest....

Giv ur best to d world.
Nd d best will cm back to u.....

Regards,
Dipanjan.....

3) Two train are running on the line in the same direction at the speed of 50 km /hr. and 30 km/hr. Given that the faster train crosses a man in the slower train in 18 seconds.What is the length of the faster train?
a) 170 m   b) 100 m  c) 98 m  d) 85 m

Soln. Relative speed of d faster train:(50-30)km./hr=20km./hr.

        Length of faster train:18/3600 x 1000 x 20=100m.
So option (b) is correct....

Giv ur best to d world.
Nd d best will cm back to u.....

Regards,
Dipanjan.....      

Thanks Nishit and Dep.smart ...but sum1 try Q2 & Q4 also...
I am simply nt getting wat the Q4 wanna say...

2) On a river Q is the mid point between two points P and R on the same bank of the river .A boat can go from P to Q and back in 12 hours and from P to R in 16 hours.How long would it take to go from R to P?
a) 3(1/3) Hrs. b) 5 Hrs. c) 6(2/3) Hrs. d) None of these.

ans:

From the information given its clear
Distance PQ = QR

Time for PQ -> QP : 12
Time for PR = 2 x Time for PQ(as in same direction) = 16
=> Time for PQ = 8

and time for QP = 4

Some time for RP = 2 x 4 = 8

4) Shreya travelled the 1st half of the distance from her house to school at a speed of 10 km/hr. and for exactly half of the remaining time she travelled at 15 km/hr. and rest of the time at 20km/hr. find her average speed.
a) 13km/h  b) 12(8/11)  c) 15km/h.  d) None of these.

ANS:

Avg Speed = Total Distance / Total time

                = 2S / (S/10 + 2S/35)
               
                = 2 / (1 /10 + 2/35)

                = 140/11 (ans b)

oh it ws sooo simple..i think i ws gvng  unnecessary thot..(more thaught dan required..)
anywaz thanks..

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