UPSC CDS 2 2021 Math Paper

In the clock
θ=90+φ Where, θ→ angle travelled by minute hand
φ→ angle travelled by hour hand
We know that, 360∘ of minute hand
=30∘ of hour hand
∴‌

φ

θ

=‌

30∘

360∘

⇒‌‌φ=‌

θ

12

⇒‌‌θ=12φ
⇒90+φ=12φ
[∵θ=90+φ]
⇒‌‌90=11 φ ⇒‌‌φ=‌

90

11

≈8.2
∴12φ=12×8.2=98.4
360∘ angle means →60min.
96∘ angle means →16min
102∘ angle means →17min
∴98.4∘ will be meant between 16 to 17min.
Hence, option (b) is correct.