Question

the hour and hands of a clock are 4.2 cm and 7 cm long respectively. find the sum of the distances covered by their in 1 day

Answer 1

minute hand is 7 cm long
so distance covered by it in one round is
$2\pi r$
which is circumference of a circle
so total dist covered by it in one round is
2(22/7)(7)
44 cm
as 1 round means 1 hour
and a day has 24 hours
so total distance covered by it in a day is
44 × 24 cm
1056 cm
and now coming on hour hand
it is 4.2 cm long
similarly distance covered by it in one round is
2(22/7)(4.2)
26.4 cm
and as one round of hour hand refers to 12 hours and one day contains 24 hours
so total distance covered by it in one day is
2 × 26.4 cm
52.8 cm
and total sum of both distances is
1056 + 52.8 cm
1108.8 cm
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