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A car travels a distance of x with speed v₁ and then the same distance x with speed v₂ in the same direction. The average speed of the car is

Asked in JEE Main 25th Jan 1st Shift 2023 · Distance and average speed

• (1) (v₁v₂)/(2(v₁ + v₂))
• (2) (2x)/(v₁ + v₂)
• (3) (2v₁v₂)/(v₁ + v₂)
• (4) (v₁ + v₂)/2

Step-by-step solution

Why the other options are wrong

• (1) A quarter of the harmonic mean; no single slip produces it.
• (2) Divides the total distance by the sum of the speeds instead of by the total time; the result has the dimensions of time, not speed.
• (4) Arithmetic mean, valid for equal times.

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