Beaten By Problems in Race with Distance and Speed Tricks

Beaten By Problems in Race involve comparing the distances covered or times taken by two runners. The standard cases are when one runner beats another by a certain distance or by a certain number of seconds. Use speed ratios, time differences and relative speed to solve these questions accurately.

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What Are Beaten By Problems in Race?

In a race, if A beats B by d metres in a race of length L metres, A covers L metres while B covers only L − d metres when A finishes. Therefore, their speed ratio is A:B = L:(L − d).

For the same race, time is inversely proportional to speed. Hence, the time ratio of A and B is (L − d):L. If A beats B by t seconds, and A takes T seconds, then B takes T + t seconds and their speed ratio is (T + t):T.

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Race Problems: Head Start and Dead Heat

Learn to solve race problems involving head starts, dead heats, and beaten-by conditions using relative speed and distance relationships.

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Beaten By Problems in Race Formula & Tricks

Important Formulas

Speed ratio when beaten by distance
A:B speed = L:(L − d)

If A wins a race of L metres by d metres, B has covered L − d metres when A finishes.

Time ratio when beaten by distance
A:B time = (L − d):L

For the same distance, time is inversely proportional to speed.

Time difference from distance difference
If A's time is T, B's time = TL ÷ (L − d)

This gives the time taken by B to complete the full race when A beats B by d metres.

Speed ratio when beaten by time
A:B speed = (T + t):T

If A finishes in T seconds and beats B by t seconds, B finishes in T + t seconds.

Time of the winner from both differences
T = t(L − d) ÷ d

If A beats B by d metres in an L-metre race and by t seconds, this gives A's time.

Quick Tricks

Use the distance covered by the loser

When the winner finishes, subtract the winning margin from the total race length. Do not add the margin to the race length.

Example: In a 200 m race, A beats B by 30 m. At A's finish, B has covered 200 − 30 = 170 m, so the speed ratio is 200:170 = 20:17.
Convert a time margin into a time ratio

If the winner's time is T and the time margin is t, use winner:loser time = T:(T + t). Reverse this ratio to obtain the speed ratio.

Example: If A finishes in 16 seconds and beats B by 4 seconds, B takes 20 seconds. Therefore, A:B speed = 20:16 = 5:4.
Use the combined formula directly

When both the distance margin and time margin are given, use T = t(L − d) ÷ d to find the winner's time before calculating speeds.

Example: For L = 100 m, d = 20 m and t = 4 s, A's time is 4 × 80 ÷ 20 = 16 s.

Beaten By Problems in Race Concepts

Race Problems Based on Distance Margin

If A beats B by d metres in an L-metre race, the speed ratio of A to B is L:(L − d).

At the instant A reaches the finish line, B is d metres behind and has covered L − d metres. Since both runners are considered over the same time interval, their speeds are proportional to these distances.

Example: In a 150 m race, A beats B by 30 m. B covers 120 m when A finishes, so A:B speed = 150:120 = 5:4.

Race Problems Based on Time Margin

If A beats B by t seconds and A takes T seconds, then B takes T + t seconds and A:B speed = (T + t):T.

Both runners cover the same race distance, so speed is inversely proportional to time. The runner taking fewer seconds has the greater speed.

Example: A completes a race in 18 seconds and beats B by 3 seconds. B takes 21 seconds, so A:B speed = 21:18 = 7:6.

Finding Time from Distance and Time Margins

When A beats B by d metres and t seconds in an L-metre race, A's time is T = t(L − d) ÷ d.

The distance condition gives A:B speed = L:(L − d). Therefore, their time ratio is (L − d):L. The difference between these times is t, which leads to the formula.

Example: A beats B by 25 m in a 125 m race and by 5 seconds. A's time = 5 × (125 − 25) ÷ 25 = 20 seconds. B's time is 25 seconds.

Finding Speed or Race Length

After finding the speed ratio, use the known speed or distance to calculate the unknown quantity.

If A:B speed = p:q and A's speed is v, then B's speed is vq ÷ p. If the race length is unknown but the distance margin and speed ratio are known, use L:(L − d) = p:q and solve for L.

Example: A beats B by 20 m, and their speed ratio is 5:4. Thus L:(L − 20) = 5:4, so 4L = 5L − 100 and L = 100 m.

Beaten By Problems in Race Data Table

Use the structured data below while following the explanation and examples.

Core Race-Margin Relations

Formulas for comparing two runners when one runner beats the other.

Given condition Winner's quantity Loser's quantity Required ratio
A beats B by d metres in an L-metre race A covers L metres B covers L − d metres A:B speed = L:(L − d)
A beats B by t seconds A takes T seconds B takes T + t seconds A:B speed = (T + t):T
A beats B by d metres and t seconds A takes t(L − d) ÷ d seconds B takes tL ÷ d seconds A:B speed = L:(L − d)

Note: L, d and distances must use the same unit. Time values must use the same unit.

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Quick Revision Notes

Beaten By Problems in Race: Revision Points

Use these direct rules to revise race-margin calculations.

  • If A beats B by d metres in an L-metre race, B covers L − d metres when A finishes.
  • Speed ratio A:B = L:(L − d).
  • Time ratio A:B = (L − d):L for the same race.
  • If A takes T seconds and beats B by t seconds, B takes T + t seconds.
  • For a time margin, speed ratio A:B = (T + t):T.
  • If both margins are given, winner's time = t(L − d) ÷ d.
  • Keep all distances in one unit and all times in one unit before applying a formula.

Beaten By Problems in Race FAQs

What is the beaten by distance formula in a race?

If A beats B by d metres in an L-metre race, A:B speed = L:(L − d). For example, in a 100 m race with a 20 m margin, the speed ratio is 100:80 = 5:4.

If A beats B by 20 m in a 100 m race, what distance does B cover when A finishes?

B covers 100 − 20 = 80 m when A reaches the finish line.

A finishes a race in 16 seconds and beats B by 4 seconds. What is their speed ratio?

B takes 16 + 4 = 20 seconds. Since speed is inversely proportional to time, A:B speed = 20:16 = 5:4.

How do you find the winner's time when both race margins are given?

Use T = t(L − d) ÷ d, where L is the race length, d is the distance margin and t is the time margin. For L = 100, d = 20 and t = 4, T = 16 seconds.

If A beats B by 30 m in a 150 m race, what is the time ratio?

B covers 120 m when A finishes. Therefore, A:B time ratio = 120:150 = 4:5.

A beats B by 20 m in a race, and their speed ratio is 5:4. What is the race length?

Use L:(L − 20) = 5:4. Thus 4L = 5L − 100, giving L = 100 m.

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