Quantitative Aptitude - Arithmetic Ability Questions

What is the value of Sin 30- √2 Cos 30

A, B and C can do a job working alone in 6, 9 and 18 days respectively. They all work together for 1 day, then A and B quit. How many days C working alone will take to complete the remainder of the job?

A train runs at 80 kmph for the first 40 km and the next 30 km at 60 kmph. Find the average speed.

The ratio of present ages of Ratnabali and Shaukat is 8:5. After 22 years the ratio of their ages will be 10:9. At present, what is Ratnabali's age?

α and β are the roots of the quadratic equation x2 – x – 1 = 0. What is the value of α8 + β8?

A sum of Rs. 3000 yields an interest of Rs. 1080 at 12% per annum simple interest in how many years ?

What is the ratio of simple interest earned on certain amount at the rate of 12% for 6 years and that for 12 years?

A solid cone of height 36 cm and radius of base 9 cm is melted to form a solid cylinder of radius 9 cm and height 9 cm. What percent of material is wasted this process?