The sum of the squares of 3 natural numbers is 1029, and they are in the proportion 1 : 2 : 4. The difference between the greatest number and the smallest number is:
Show answer & explanation
Correct answer: B
Explanation
The correct answer is option 2 i.e 21
Let the three natural numbers be y, 2y, & 4y.
⇒ y2 + (2y)2 + (4y)2 = 1029
⇒ 21y2 = 1029
⇒ y = 7 (y can't be -7 because we are dealing with natural numbers)
⇒ The difference between greatest number and smallest number =4y - y
⇒ 3y = 21