In a school, after prayer classes start at 8 : 25 am. If each period is of 35 minutes, then fourth period will start at :

Correct option is D

Given
Starting time = 8 : 25 am Duration of each period = 35 minutes
Formula / Concept used
Start time of nth period = Starting time + (n − 1) × duration of each period
Solution
Fourth period means after completion of first three periods.
Time for 3 periods = 3 × 35 minutes = 105 minutes 105 minutes = 1 hour 45 minutes
Add this to starting time: 8 : 25 am + 1 hour 45 minutes = 10 : 10 am
The correct option is (d)