If $${\sqrt{7-2}\over\sqrt{7+2}}=a\sqrt{7}+b$$, then the value of a is : 

If $$ {x^2} -4x-1 $$ then the value of $$ {{x^6} -{x^4}+{x^2}-1}\over {x^3}$$ will be

Direction: Study the following graph carefully and answer the following questions.

What is the ratio of companies having more demand than production to those having more production than demand?

If sin²a = cos³a then the value of cot⁶ a – cot²a? 

Direction: The bar graph shows revenues in rupees lakhs from selling four different products (A, B, C and D) by a certain company. Study the diagram and answer the following questions.

By what value (in %) the revenue from sale of product B in 2016 was greater than that of 2015?

Answer the following questions

P, Q and R alone can complete a piece of work in 24, 36 and 18 days respectively. P started working, after 2 days R joins with them and Q joins with them after another 2 days, then find the no of days P, Q and R worked together.

The cost price of a radio is₹  600. The 5% of the cost price is charged towards transportation. After adding that, if the net profit to be made is 15%, then the selling price of the radio must be

The product of two consecutive even numbers is 168. Find the sum of the numbers?