Question

QUESTION
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Our newly 24 hours digital clock behaves as follows:
• At every half-an-hour, time is shifted back by 15 mins
At every hour, time is fast forwarded by 15 mins.
Say, initial time for conventional clock and newly designed clock is 10:00, what would be the time in our newly designed clock
when conventional clock shows 19:30?
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Answer 1

ANSWER = 17 hrs

QUESTION

At every half an hour , time is shifted back by 15 minutes. At every hour time is fast forwarded by 15 minutes say , initial time for conventional clock and in our newly designed clock is 10.00 find the time of new clock at 19.30

SOLUTION

here there are a number of points to note

• at every half an hour , time backwards by 15 minutes
• at every hours time is forwarded by 15 minute

That is at every hour , time is backwarded 15 minutes 2 times and forwarded 15 minute 1 time

Let's consider an hour of this new clock,

time at 1 hr = 1 hr - ( 2×15 ) + 15 minute

= 60 minute - 30 + 15

= 60 minute - 15

= 45 minute

ie , when time is showing 1 hr in convention clock the time at new clock is 45 minute.

NOW COMING UP TO THE PROBLEM

Time at conventional clock = 10 :00

time at new clock = 10.00

time at conventional clock = 19.30

difference in time = 9. 30 hr

for 1 hr minute is 15 minute is backwarded

for 9 hr = 135 minute is backwards

remaining = 9 × 60 - 135

= 405 minute

for 30 minute, 15 minute is backwarded

remaining = 15 minute

total time

remaining = 405 + 15 = 420 minute

converting to hrs = 420 / 60

= 7 hrs

time shown in digital clock = 10 + 7

= 17 hrs