QUESTION

CSAT

Medium

Reasoning

Prelims 2019

A wall clock moves 10 minutes fast in every 24 hours. The clock was set right to show the correct time at 8:00 a.m. on Monday. When the clock shows the time 6:00 p.m. on Wednesday, what is the correct time?

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Explanation

Understand the Clock's Error:

  • The clock gains 10 minutes every 24 hours.

Calculate the Total Time Elapsed:

  • From 8:00 a.m. on Monday to 6:00 p.m. on Wednesday is 2 days and 10 hours.
  • Convert this to hours: 2 days ×\times 24 hours/day = 48 hours.
  • Add the extra 10 hours: 48 hours + 10 hours = 58 hours.

Determine the Clock's Gain in 58 Hours:

  • The clock gains 10 minutes every 24 hours.
  • In 58 hours, the gain is: (58 hours /24 hours)×10 minutes=24.17 minutes(58 \text{ hours } / 24 \text{ hours}) \times 10 \text{ minutes} = 24.17 \text{ minutes}.

Calculate the Correct Time:

  • The faulty clock shows 6:00 p.m.
  • Subtract the gain of 24.17 minutes: 6:00 p.m. - 24.17 minutes \approx 5:35 p.m.

Round to the Nearest Minute:

  • Rounding 5:35 p.m. to the nearest minute gives 5:36 p.m.

Therefore, the correct time when the faulty clock shows 6:00 p.m. on Wednesday is approximately 5:36 p.m.

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