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. . Read full Tips & Tricks
ഗണിത സൂത്രവാക്യം
ആദ്യത്തെ \'n\' എണ്ണൽ സംഖ്യകളുടെ തുക = n(n+1) /2. ആദ്യത്തെ \'n\' ഒറ്റ സംഖ്യകളുടെ തുക = n². ആദ്യത്തെ \'n\' ഇരട്ട സംഖ്യകളുടെ തുക = n(n+1). ആദ്യത്തെ \'n\' എണ്ണൽ സംഖ്യകളുടെ വർഗ്ഗങ്ങളുടെ തുക = n(n+1)(2n+1) / 6. ആദ്യത്തെ \'n\' എണ്ണൽ സംഖ്യകളുടെ ക്യൂബുകളുടെ തുക = [n(n+1)/ 2]². ആദ്യ പദം \'a\', പൊതു വ്യത്യാസം \'d\' ആയാൽ n-മത്തെ പദം കാണാൻ = a+ (n -1) d. ആദ്യ പദം \'a\', പൊതു വ്യത്യാസം \'d\' ആയാൽ, n പദങ്ങളുടെ തുക കാണാൻ = n/2[2a + (n - 1)d]. ആദ്യ പദവും (t1), n Read full Tips & Tricks
BODMAS Rule
BODMAS is an acronym and it stands for Bracket, Of, Division, Multiplication, Addition and Subtraction. .
This explains the order of operations to solve an expression. According to Bodmas rule, if an expression contains brackets ((), {}, []) we have to first solve/simplify the bracket followed by of (powers and roots etc.), then division , multiplication , addition and subtraction from left to right. .
What is the divisibility by 2 Rule?. Even numbers are multiples of 2. A number is even if ends in 0,2,4,6, or 8. What is the divisibility by 3 rule?. A number is divisible by 3 if the sum of its digits is divisible by 3. 372, for instance, is divisible by 3 since sum of its digits (3+7+2) is 12. And 12 is divisible by 3. What is the divisibility by 4 rule?. A number is divisible by 4 if the number\'s last two digits are divisible by 4. 9,312, for instance, is divisible by 4 since its last 2 digits are 12. And 12 is divisible by 4. What is the divisibility by 5 rule?. A number is divisible by 5 if its last digit is a 0 or 5. What is the divisibility by 6 rule?. Since 6 is a multiple of 2 and 3, the rules for divisibility by 6 are a combination of the rule for 2 and the rule for 3. Divisibility by 8 Rule. A number passes the test for 8 if the las Read full Tips & Tricks