Question
A man goes to a place on bicycle at speed of 16 km/hr and comes back at lower speed. If the average speed is 6.4 km/hr in total journey, then the return speed (in km/hr) is :
Answer: Option B
Answer: (b)Let the speed of cyclist while returning be x kmph.Average speed = ${2 × 16 × x}/{16 + x}$6.4 = ${32x}/{16 + x}$6.4 × 16 + 6.4x = 32x32x - 6.4x = 6.4 × 1625.6x = 6.4 × 16$x = {6.4 × 16}/{25.6}$ = 4 kmph.
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Answer: (b)Let the speed of cyclist while returning be x kmph.Average speed = ${2 × 16 × x}/{16 + x}$6.4 = ${32x}/{16 + x}$6.4 × 16 + 6.4x = 32x32x - 6.4x = 6.4 × 1625.6x = 6.4 × 16$x = {6.4 × 16}/{25.6}$ = 4 kmph.
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