At what approximate time between 4 and 5 am will the hands of a clock be at right angle?
At what approximate time between 4 and 5 am will the hands of a clock be at right angle?
Answer/Solution
4 : 38 am
Steps/Work
Here H × 30 = 4 × 30 = 120°.
(Since initially the hour hand is at 4. ∴ H = 4).
Required angle A = 90° and since, H × 30 > A° so, there will be two timings.
Required time T = 2⁄11(H × 30 ± A) minutes past H.
∴ One timing = 2⁄11(4 × 30 + 90) minutes past 4
= 382⁄11 minutes past 4.
Or 4 : 38 approx.
Answer B
(Since initially the hour hand is at 4. ∴ H = 4).
Required angle A = 90° and since, H × 30 > A° so, there will be two timings.
Required time T = 2⁄11(H × 30 ± A) minutes past H.
∴ One timing = 2⁄11(4 × 30 + 90) minutes past 4
= 382⁄11 minutes past 4.
Or 4 : 38 approx.
Answer B