Quantitative Aptitude - Arithmetic Ability Questions

From the top of a platform 5 m high, the angle of elevation of a tower was 30 deg. If the tower was 45 m high, how far away from the tower was the platform positioned?

The value of k, for which the quadratic equation 4x2 + 4√3x + k = 0 has equal roots is

In ΔPQR measure of angle Q is 900. If sinP = 12/13, and PQ = 1cm, then what is the length (in cm) of side QR?

If the measure of the interior angle of a regular polygon is 120 deg then how many sides does it have?

What is the effective discount (in %) on two successive discounts of 20% and 10%?

A boat goes 15 km upstream and 10 1/2 km down stream in 3 hrs 15 min. It goes 12 km upstream and 14 km downstream in 3 hrs. What is the speed of the boat in still water?

R is 80% more efficient than S. If S alone can make a book in 90 days, then R alone can make the book in how many days?

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.