Question 89

The descending order of the numbers $$5\sqrt{6}, 10\sqrt{3},Ā 7\sqrt{5},Ā 6\sqrt{7}$$ is

Solution

This question can be resolved by knowing approximate values of the square roots of 3, 5, 7.Ā 
Sqrt(3) = 1.73 approx., sqrt(5) = 2.23 approx., sqrt(7) = 2.6 approx.

Now, we can see thatĀ $$10\sqrt{\ 3}$$ will be larger than 17 whileĀ $$7\sqrt{\ 5}$$ would be a little over 15.Ā 
While in contrast,Ā $$5\sqrt{\ 6}$$ would not even be 15.Ā 
Also,Ā $$6\sqrt{\ 7}$$ would be greater than 15.Ā 

Hence, we can say thatĀ $$10\sqrt{\ 3}$$ is the largest of them all andĀ $$5\sqrt{\ 6}$$ would be the smallest.Ā 
$$6\sqrt{\ 7}\ >\ 7\sqrt{\ 5}\ $$.Ā 
Hence, answer is B


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