Quantitative Aptitude - Arithmetic Ability Questions

The average weight of 30 students in a class is 25 kgs. If the weight of the class teacher is added, the average weight increase by 2 kgs. The weight of the class teacher in kgs is

In the following question, four number pairs are given. The number on left side of (–) is related to the number on the right side of (–) with some Logic/Rule/Relation. Three are similar on basis of same Logic/Rule/Relation. Select the odd one out from the given options.

If 2cos2A - 1 = x, then the value of x is

The simplified form of (x + 3)2 + (x - 1)2 is

If the standard deviation of a population is 6.5, what would be the population variance?

Identify the odd one out from the following:

If the areas of two similar triangle are in the ratio 5 : 7, then what is the ratio of the corresponding sides of these two triangles?

Of the 3 numbers whose average is 40, the first is 1/3 rd the sum of other 2. What is the first number?