An interesting number properties question that tests your understanding of odd numbers, even numbers and inequalities. The best thing about a question of this kind is that there is no formula to get the answer. Try the question before checking out the solution video. Question If x is a positive … [Read more...]

## Number properties – Factorial

How many trailing zeroes does 60! have?(A) 12(B) 9(C) 15(D) 14(E) 13 … [Read more...]

## Permuations and digits

1. How many six digit positive integers comprising only the digits 1 and 2 exist such that the number is divisible by 3?For a number to be divisible by 3, the sum of the digits must be divisible by 3.Case 1: 111111: This can rearrange in only one way.Case 2: 222222: This can rearrange in only one … [Read more...]

## Descriptive statistics – Standard Deviation

If m is the arithmetic mean (average) of 4 integers a, b, c, and d and s is the standard deviation of the 4 integers and s = , then is s > 0?(1) m > a(2) a + b + c + d = 0Solution:s will be zero only in two instances: (i) when all the elements in the set are the same, or (ii) the set contains only … [Read more...]