A class starts at 10 a.m. and lasts till 1.27 p.m. Four periods are held during this interval. After every period, 5 minutes are given free to the students. The exact duration of each period is
(a)42 minutes
(b)48 minutes
(c)51 minutes
(d)53 minutes
Answer
Answer (as printed): B
Explanation
Time between 10 a.m. and 13.27 hours $=3$ hrs. 27 min. $=207 \mathrm{min}$. Total duration of free time $=(5 \times 3) \mathrm{min}=15 \mathrm{min}$. Remaining time $=(207-15) \mathrm{min} .=192 \mathrm{min}$. ∴ Duration of each of the 4 periods $=\left(\frac{192}{4}\right) \min .=48 \mathrm{min}$.