Quantitative Aptitude - Arithmetic Ability Questions

If a boat goes upstream at a speed of 21 km/h and comes back the same distance at 28 km/h. What is the average speed (in km/hr) for the total journey?

Ram and Shyam undertook a work for Rs 5600. Ram alone can do the work in 5 days and Shyam alone can do the work in 9 days. If they worktogether, then what will be the difference (in Rs.) in the amount they receive?

Point Q(-1,b) is the midpoint of segment EF. Co-ordinates of point E are (-4,a) and point F are (2,0). What is the value of a and b?

If (4a-3)2=0,then the value of 64a3+12a+13 is

There are red (A), yellow(B) and green (C) tokens in a bag. A : B :: 3 : 8, B : C :: 6 : 13. A : B : C is given by

If a = 1/a-5, then the value of a + 1/a = ?

What is the unit digit of 15+25+35+...+205 ?

If 3x - 10 = -(2x + 5), then the numerical value of (x - 4)3 is