Quantitative Aptitude - Arithmetic Ability Questions

A car travels a certain distance at 24 km/h and comes back at 36 km/h. Find the average speed for total journey.

If a+b-62+a2b2+1+2b=2ab+2a, then the value of a is 

Find the odd one out.

If cosπ/4c - tanπ/4c = x, then x is

D and E are points on the sides AB and AC respectively of ΔABC such that DE is parallel to BC and AD:DB = 4:5, CD and BE intersect each other at F. Then the ratio of the areas of ΔDEF and ΔCBF

A discount series of 15%, 20% and 25% is equal to the single discount of?

If x = 1 + √2 + √3, then the value of x2-2x-4=0

A man can row upstream at 12 km/hr and downstream at 18 km/hr. The man's rowing speed in still water is