The difference between two positive numbers is 3. If the sum of their squares is 369, then the sum of the numbers is
Correct Answer: Option C
Let the two numbers be a and b
Now as per the given information,
a – b = 3 ….(1)
a2 + b2 = 369 …..(2)
From (1), a = b + 3
Put the value of a in equation (2)
a2 + b2 = (b + 3)2 + b2 = b2 + 9 + 6b + b2 = 369
⇒ 2b2 + 6b + 9 = 369
⇒ 2b2 + 6b – 360 = 0
⇒ b2 + 3b – 180 =0
⇒ (b - 12) (b + 15) = 0
⇒ b = 12 (b is not equal to 15 because b is positive)
Put the value of b in equation (1)
∴ a = 12 + 3 = 15
Thus sum of two numbers = a + b = 15 + 12 = 27.
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