A can go round a circular path 8 times in 40 | vedclass

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Question

(C) Let the original diameter be $D$ and the original circumference be $C = \pi D$.Time taken for $8$ rounds = $40$ minutes.Time taken for $1$ round =

Vedclass · Accepted Answer

$50$

Vedclass · Answer

(C) Let the original diameter be $D$ and the original circumference be $C = \pi D$.Time taken for $8$ rounds = $40$ minutes.Time taken for $1$ round = $40 / 8 = 5$ minutes.Speed $v = \frac{	ext{Distance}}{	ext{Time}} = \frac{C}{5} = \frac{\pi D}{5}$.New diameter $D' = 10D$.New circumference $C' = \pi D' = 10 \pi D = 10C$.Since the speed $v$ remains the same,the new time $T'$ required to complete $1$ round is:$T' = \frac{C'}{v} = \frac{10C}{C/5} = 10 	imes 5 = 50$ minutes.

$A$ can go round a circular path $8$ times in $40$ minutes. If the diameter of the circle is increased to $10$ times the original diameter,then the time required by $A$ to go round the new path once,travelling at the same speed as before,is (in $min$)

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