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.

If three successive discounts of 20%, 30% and 40% are given, then what will be the net discount (in percentage)?

In triangle ABC, ∠ABC = 90°. BP is drawn perpendicular to AC. If ∠BAP = 30°, then what is the value (in degrees) of ∠PBC?

In a triangle ABC, if ∡A +∡C = 140° and ∡A + 3∡B = 180°, then ∡A is equal to

If X and Y are the two digits of the number 347XY such that the number is completely divisible by 80, then what is the value of X + Y?

If cos(A-B) - cos(A+B) = x, then the value of x is

If ABCD is a Cyclic Quadrilateral, then the value of Cos2A - Cos2B - Cos2C + Cos2D is

The rate of discount on an article whose marked price is Rs. 170 and selling price is Rs. 130?