time and distance Model Questions & Answers, Practice Test for ibps rrb po officer scale 1 prelims 2024

Answer: (a)

A runs 5 rounds, B runs 4 rounds (ratio of speed)

A passes B each time A has run 5 rounds or

5x $1/4 = 5/4km = 1 1/4$ km

1 $1/4$ km is contained in 4 km 3 times

hence A passes B thrice

Answer: (d)

Let the average speed be x km/h.

and Total distance = y km. Then,

$0.2/10y+0.6/30y+ 0.2/20y= y/x$

⇒$x=1/0.05$=20km

Answer: (a)

Let the total distance be d km

Then, time taken to cover $1/3$ d distance

$t_1 = {1/3 d}/x = d/{3x}$

Remaining distance = d - $1/3 d = 2/3 d$ = km.

Now, time taken to cover $2/3$ rd distance,

$t_2 = {2/3 d}/{2y} = {2d}/{6y}$

Time taken to cover distance from A to B and B to A.

t = ${2d}/{6z}$

According to the question, $t_1 + t_2$ = t

⇒$d/{3x} + {2d}/{6y} = {2d}/{6z}⇒1/{3x} + 1/{3y} = 1/{3z}$

⇒$1/x + 1/y = 1/z$

Answer: (a)

Relative speed = (p – q) km/hr.

Time taken to cover the c km = $c/{p - q}$ hr

Distance travelled by A before he overtakes

B = ${qc}/{p - q}$ km

Answer: (a)

Let the speed of a train be v m/s and length of train be x m.

when cross the pole in time t = 10 s

Time = ${\text"Distance"}/{\text"Speed"}$

⇒10 = $x/v$⇒x = 10 v ... (i)

When cross the platform in time, t = 20 s

20 = ${x + 200}/v$⇒20v = x + 200

⇒20v = 10v + 200 [from Eq. (i)]

⇒10v = 200

∴ v = 20

From Eq. (i),

x = 10v = 10 × 20 = 200 m