Speed, Distance & Time · Topic 1 of 5

🔺 Speed–Distance–Time Basics

1 exam question type, fully solved

Every motion question links three things — distance, speed and time. Learn the one triangle that connects them and the single conversion that switches between km/h and m/s, and most questions become a one-line division.

The s–d–t triangle & the 5/18 switch

Put distance on top, speed and time underneath. Cover the one you want and read off the rest: , , .

• Units must agree. km/h needs distance in km and time in hours, so turn minutes into hours by dividing by 60.

• km/h to m/s: multiply by (number shrinks). m/s to km/h: multiply by (number grows).

• Fixed distance ⇒ inverse proportion: if the road length is constant, speed and time flip — a speed ratio of means a time ratio of . No need to find the distance.

• Memorise the ladder: km/h m/s, so .

📐DST ToolkitThe triangle & the 5/18 switch

Cover the one you want — click any letter

Select D, S, or T above

A train covers 240 km at 60 km/h, so it takes hours.

Convert 90 km/h to m/s: m/s.

Q1A cyclist covers 72 km at 12 km/h. How much time does it take?

Q2A train moves at 108 km/h. What is this speed in m/s?

Q3A train covers a distance in 10 hrs at 80 km/h. At 100 km/h, how long does it take?

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Real exam questions — Speed–Distance–Time Basics

1 question types · 5 solved examples from real SSC papers

Master the speed-distance-time triangle and the km/h to m/s conversions that show up in almost every motion question.

How to solve this type

Every speed problem ties together three quantities: distance, speed and time. Picture the s-d-t triangle with distance on top, speed and time below. Cover the one you want and read off the rest:

s=\dfrac{d}{t}

d=s\times t

t=\dfrac{d}{s}

. The single most important rule before you compute: the units must agree. If speed is in km/h, then distance must be in km and time in hours. So always change minutes to hours by dividing by 60. To go from km/h to m/s, multiply by

\dfrac{5}{18}

(the number gets smaller). To go from m/s to km/h, multiply by

\dfrac{18}{5}

(the number gets bigger). One more idea you will reuse constantly: when the distance is fixed, speed and time are inversely proportional, so if speed becomes

\dfrac{4}{5}

, the time becomes

\dfrac{5}{4}

. Memorise the small table

18

km/h

=5

m/s, so

36=10

54=15

72=20

90=25

108=30

A train travels 330 km at 66 km/h. Time taken?

A5 hrsB4 hrsC4.5 hrsD6 hrs

A car travelling at 60 km/h reaches in 5 hrs. At what speed should it travel to reach in 4 hrs?

A70 km/hB75 km/hC72 km/hD80 km/h

Convert 72 km/h to m/s.

A25.92 m/sB20 m/sC18 m/sD24 m/s

A speed of 25 m/s equals how many km/h?

A90 km/hB100 km/hC80 km/hD72 km/h

Neha walks at 8 km/h and crosses a bridge in 27 minutes. Length of bridge (in metres)?

A3000 mB2400 mC3600 mD4850 m