Question

A train crossestwo person cyclying in the same direction, in 12 second and 15 seconds respectively.if the speed of the two cyclyst are 10 kmph and 12 kmph, then find the length and speed of train.

Answer 1

dumbcow help me............

Answer 2

speed = 20kmph andlength =100/3 meter but dont kno hw to solve

Answer 3

not sure on this one
does it take 15 sec to pass both

Answer 4

no 12 sec and 15 sec respectively

Answer 5

ok got it
d = r*t
r is speed of train
d is distance of train
t is time it take to pass each cyclist

also need to convert from km/hr to m/s
1km/hr = 10/36 m/s
cyclist 1:
d = (r-10)(10/36)*(12)
cyclist 2:
d = (r-12)(10/36)*(15)

to find r set 2 equations equal
(r-10)(10/36)*12 = (r-12)(10/36)*(15)
(10/36) cancels
12r -120 = 15r - 180
-3r = -60
r = 20

substitute this back in to find d
d = (20-10)(10/36)*12
d = 1200/36
d = 100/3

Answer 6

Let the speed of the train be v
Thus, the relative speed of c1 = v-c1=v-10
the relative speed of c2 = v-c2=v-12

Now,
speed = length of the train/time to cross the cycle
v-10=L/12
and
v-12=L/15
Therefore L/12+10 = L/15+12
L+120/12=L+180/15
15L+120*15 = 12L + 12*180
3L = 12*180 - 120*15
L = 4*180 - 40*15
=40(18-15)
=40(3)
120.

Answer 7

you forgot to convert to m/s for speed because time is in sec

Answer 8

I didn't

Answer 9

Ya right, sorry!

Answer 10

I don't know why they haven't given the option to delete answers!

Answer 11

amit did that help you understand

Answer 12

yes