Question

14. A bus crosses two people cycling at the speed of 9.6
km/hr and 12 km/hr in the same direction as that in
which the mini van is heading in 4.5 seconds and 9
seconds respectively. What is the length of the bus ?
(A) 7 m
(B) 6 m
(C) 4 m
(D) 8 m​

Answer 1

Answer:

(c) 4m

Step-by-step explanation:

let speed of bus=x

speed of cycle 1 (c1)=9.6km/hr =9.6×1000/3600 m/s

speed of cycle 2(c2)=12 km/hr= 12×1000/3600 m/a

time taken by bus to cover cycle 1 = 4.5 sec

time taken by bus to cover cycle 2 =9 sec

relative speed of bus with cycle 1= x-c1

relative speed of bus with cycle2= x-c2

now,

length of bus,

(x-c1)×4.5=(x-c2)×12

(putting all values in the eqn. we will get the value of x)

here x= 4m

Answer 2

Step-by-step explanation:

Bus Speed is A

(A-9.6)*4.5=(A-12)*9

so A=14.4 km

train length relative speed

(14.4-9.6)5/18*4.5

6m