If a² + a + 1 = 0 then the value of a⁹ is. 

Direction: what should come in place at question mark(?).

45% of 224×?% of 120=8104.32

Simplify the following equation
$$ {\sqrt{(1-sin^{2}θ) ÷{(1-cos^{2}θ)}}}$$

In a garden of 42 trees, 3/7 of them are Neem trees and the rest are Mango trees. Find the number of Mango trees.

If the sum and difference of two number are 20 and 8 respectively, then the difference of their squares is: 

A bag has Rs.420 in the denomination of Rs.1, Rs. 2 and Rs. 5 coins. The number Rs.1, Rs.2 and Rs.5 coins are in the ratio of 8: 1:5. How many coins of Rs.5 are in the bag?

If the average of 11, 23 and x is 40, then what is the value of x?

The value of $${4- \sqrt{0.04} \over 4+\sqrt{0.4} } $$  is closed to