Handshake Problem
Handshake ProblemSuppose there are n people in the party. The first person shakes hand with the other (n-1) guests. The second guest shakes hand with the other (n-2) guests. this will continue until the (n-1) th guest shakes hand with the nth guest.
Total number of handshakes is (n-1) + (n-2)... + 3 + 2 + 1.
= ((n-1)(n))/2
For example, 6 people in a party shake hand with other guests. So how many handshakes will be there?
=((6-1)(6))/2
=15.
These are the different type of questions asked from this topic.
Type 1: Find the time when the angle between the two hands are given.
Type 2: Find the angle between the 2 hands when the time is given.
Type 3: Find the time, when clocks gaining/losing time.
Type 4: Find the time in the mirror image.
ക്ലോകിലെ ഓരോ അക്കങ്ങൾക്കിടയിലെ കോണളവ്= 30°.
മിനിറ്റ് സൂചി ഓരോ മിനുറ്റിലും 6° ചുറ്റും.
മണിക്കൂർ സൂചി ഒരു മിനുറ്റിൽ ½°ചുറ്റും.
ഒരുദിവസം Hour, Minute സൂചികൾ 22 തവണ ഒന്നിന് മീതെ ഒന്നായി വരും.
ക്ലോകിലെ സൂ...
Permutation and combination related questions are common in PSC and Bank exams.
Before going to Combinations and Permutations, first lean about factorial. .
If n is a positive integer then, factorial of n is denoted as n! . .
4! = (1 x 2 x 3 x 4 ) = 24.
Permutations are for lists of items, whose order matters and combinations are for group of items where order doesn’t matter. in other words, .
When the order of items doesn\\\'t matter, it is called as Combination.
When the order of items does matter it is called as Permutation.
The number of permutations of n objects taken r at a time is determined by using this formula:.
C(n,r)=n!/((n−r)!r!) .
Combination : Picking a team of 3 people from a football coaching group of 10. C(10,3) = 10!(3!(10−3)!) = 120. ....
The quickest way to calculate percentages is to multiply numbers first and handle two decimal places later.
For example, 20% of 70 is 20 x 70 = 1400, so the answer is 14. .
70% of 20 is also 14.
To calculate the percentage of 72 or 29, then round up and down to the nearest multiple (70 and 30 respectively) to get a quick approx result.
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