Question

Q. If a clock strikes once at one o’clock, twice at two o’clock and twelve time sat12o’clock and again once at one o’clock and so on, how many times will the bell be struck in the course of2 days?

• A. 624
• B. 312
• C. 156
• D. 78

Answer 1

The correct option is B 312

In two days the clock will strike 1 four times, 2 eight times, 3 twelve times etc
ie total number of strikes
= 4 +8 +12….48
=$4\times (1+2+3\dots 12)$
= $4\times 13\times 6$
=312