Quantitative Aptitude - Arithmetic Ability Questions

If a – (1/a) = b, b – (1/b) = c and c – (1/c) = a, then what is the value of (1/ab) + (1/bc) + (1/ca)?

If P=9, Q=17 then the value of p2-q2-13

What is the measure of an interior angle of a regular decagon?

The area of a trapezium is 21 sq cm, the distance between the parallel sides is 3 cm and one of the parallel sides is 8.3 cm. What is the length of the other parallel side?

The average age of a class of 6 girls is x years. Four new girls having ages x – 2, x + 2, x + 4 and x + 6 joins the class. What is the new average age (in years) of the class?

The average age of 6 members of a family is 20 years. If the age of the servant is included, then the average age increase by 25%. What is the age (in years) of the servant?

If Mohan purchase 13 articles for Rs 12 and sells all the articles at the rate of 12 articles for Rs 13, then what will be the profit percentage?

A vendor buys bananas at 7 for Rs 6 and sells at 6 for Rs 7. What will be the result?