Question 1

The sum of two numbers is 7 and the sum their squares is 23, their product is equal to:

Solution

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

It is given that $$x^2+y^2=23$$ -----------(i)

Also, $$x+y=7$$

Squaring both sides, we get :

=> $$x^2+y^2+2xy=49$$

=> $$23+2xy=49$$

=> $$2xy=49-23=26$$

=> $$xy=\frac{26}{2}=13$$

$$\therefore$$ Product of the numbers = 13

=> Ans - (D)

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