Quantitative Aptitude - Arithmetic Ability Questions

In the following question, four groups of three numbers are given. In each group the second and third number are related to the first number by a Logic/Rule/Relation. Three are similar on basis of same Logic/Rule/Relation. Select the odd one out from the given alternatives.

By what least number should 1200 be multiplied so that it becomes a perfect square?

Find the least number that must be subtracted from 98534, to get a number exactly divisible by 824.

The radius and the height of a cone are each increased by 20%. Then the volume of the cone increases by

A prime number

An angle is greater than its complementary angle by 40°. Find the measure of the angle?

Solve the following 7 x {4 + (-2) x (-3)} = ?

The angle of elevation of an aeroplane from a point on the ground is 45°. After flying for 15 seconds, the elevation changes to 30°. If the aeroplane is flying at a height of 2500 metres, then the speed of the aeroplane in km/hr. is