Question 49

The difference between two positive numbers is 3. If the sum of their squares in 369, then the 3 sum of the numbers is

Solution

Let the numbers be $$x$$ and $$y$$

Given : $$(x-y)=3$$ -----------(i) and $$x^2+y^2=369$$ ------------(ii)

Squaring both sides in equation (i), we get : $$x^2+y^2-2xy=9$$

Substituting value from equation (ii), => $$2xy=369-9=360$$

=> $$xy=\frac{360}{2}=180$$

To find : $$(x+y)=z=?$$

Now, we know that $$(x+y)^2=x^2+y^2+2xy$$

=> $$z^2=369+2(180)=729$$

=> $$z=\sqrt{729}=27$$

=> Ans - (C)


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