If 551 ÷ 29 = 19 then 5.51 ÷ 0.0019 = ?

The square root of a positive number less than 100 lies between

5-[4-{3-(3-3-6)}] is equal to:

What is the value of x $$ {0.081\over x}={0.09\over10}$$ ?

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

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: