If $$ {cot A={n\over{n+1}}}$$ and $$ {cot B={1\over{2n+1}}}$$ then what is the value of cot (A + B)?

How many number are there from 700 to 950 (Including both) which are neither divisible by 3 nor by 7?

Direction: Study the following information and answer the related questions. P, Q, R, S, T, A, B, C, D and E are employees of a company. A table shows the average age of any two employees of the company. The average age of A and B is 27.5.
i.e. average age of A & P is given as (A+P)/2=39.5

What is the ratio of ages of Q and E?

The investments made by X and Y are the ratio 3: 2. If 5% of total profit is donated and X gets ₹ 8,550 as his share of profit then what is the amount of total profit. 

The perimeter of a rectangle and equilateral triangle is equal. One side of the rectangle is also equal to the side of the triangle. Find the ratio of the areas of the rectangle and triangle?

Products pass successively through the hands of three traders and each of them sells his goods at a profit of 30% of his cost price. If the last trader sold the products for Rs.300, then how much did the first trader pay for them? 

By what fraction selling price ( S.P. ) must be multiplied to get the cost price ( C.P. ) if the loss is 20%? 

If ax - 4y = -6 has a slope of -3 / 2. What is the value of a?