Week 1, 17th OCT,2013

Quantitative section

Use of LCM 

In today's lesson you shall learn about question related to LCM.

Example: A Shining light shine at every 3 sec, another at every  5 sec and third one at 7 sec. If all shines togather, then how many seconds will pass before they all shines simultaneously together?

The answer to this question is simply by LCM of three time periods i-e 105 sec.

LCM

Resolve the given numbers into its prime factors. In each number take the prime factor with highest number and then multiply each of highest power factor.

Example: 10, 20, 30

10:               2, 5

20:               2², 5

30:               2, 3, 5

Then LCM is simply: 2² x 3x 5= 60

Examples:

1. Love Kumar takes 30 minutes to check a paper, Imran takes 25 minutes to check a paper. If they both starts checking paper at 11:00 AM.  What is the first time they will finish marking a paper at same time.

1st time they complete checking together will be simply LCM of 25 and 30

25:               5, 5

30:               2, 3, 5

Then LCM = 5 x 5 x 3 x 2 = 150 minute so time will be 1:30 PM

Note: List of other questions will updated soon.

Regards

ADMIN SKOnlineLearning