Quantitative Aptitude - Arithmetic Ability Questions

The mean of marks secured by 35 students in division A of class X is 65, 45 students of division B is 61 and that of 70 students of division C is 59. What is the mean of marks of the students of three divisions of Class X?

If A alone can do a job in 40 days then, in how many days can B alone do the job if together they can do the job in 8 days?

PQ and RS are common tangents to two circles intersecting at A and B. AB, when produced both sides, meet the tangents PQ and RS at X and Y, respectively. If AB = 3 cm, XY = 5 cm, then PQ (in cm) will be

If 2+x+2-x2+x-2-x=2,then the value of X is

In a fraction when 3 is added to its numerator and denominator it becomes 4/5. And it becomes 1/2 when 2 is subtracted from both the numerator and denominator. Find the fraction.

If x = a + 1a, y = a - 1a ,(a>0), then the value of x4+y4-2x2y2 is

If a3 + b3 + c3 - 3abc = 0, then the value of a2/bc + b2/ac - 3.

A thief is stopped by a policeman from a distance of 350 metres. When the policeman starts the chase, the thief also starts running. Assuming the speed of the thief as 7 km/h and that of police man as 12 km/h, how far the thief would have run, before he is over taken?