Quantitative Aptitude - Arithmetic Ability Questions

If 4x - 5y = -37 and 7x + y = -16, then x - y = ______

In ∆ABC, ∡A + ∡B = 75 and ∡B + ∡C = 140, then ∡B =

The mean of 10 observations is 17. One more observation is included and the new mean becomes 16. The 11th observation is

The sum of the ages of Rohit and Ankit is 78. Rohit's age is twice the age of Ankit. What is the age (in years) of Rohit?

A and B together can do a piece of work in 36 days, B and C together can do it in 24 days. A and C together can do it in 18 days. The three working together can finish the work in

In an alloy of German silver the ratio of copper to zinc was 17:7 while that of nickel to zinc was 4 :3. The ratio of copper to zinc to nickel in the alloy was

What is the value of tan 7π/4?

What is the value of (cot60 + 1/√3) ?