Quantitative Aptitude - Arithmetic Ability Questions

In an exam, the avarage marks obtained by John in English, Maths, Hindi and Drawing were 50. His average marks in Maths, Science, Social Studies and Craft were 70. If the average marks in all seven subjects is 58, his score in maths was

An equilateral triangle ABC is inscribed in a circle of radius 20√3.
The centroid of the triangle ABC is at a distance d from the vertex A. What is d equal to ?

What is that least number that must be added to the product 684 × 686 to make it a perfect square?

12 men and 16 women together can complete a work in 4 days. It takes 80 days for one man alone to complete the same work, then how many days would be required for one woman alone to complete the same work?

Expanded and simplification of (x + 3)(x - 1) will be equal to

The 3rd and 9th term of an arithmetic progression are -8 and 10 respectively. What is the 16th term?

In a triangle PQR, ∠PQR = 90 deg, PQ = 10 cm and PR = 26 cm, then what is the value (in cm) of inradius of incircle?

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?