If X and Y are two multiples of 7 then which of the following statemen

1.	If X and Y are two multiples of 7 then which of the following statement is incorrect?1. (X2 + Y2) is divisible by 72. (X2 - Y2) is divisible by 73. (X + Y) is divisible by 144. None of these
Answer» Correct Answer - Option 3 : (X + Y) is divisible by 14 Given: X and Y is multiple of 7 Concept Used: If the number is a multiple of given number then the number is also divisible by the given number Calculation: It is given in the question that X and Y are multiples of 7 ∴ X = 7m and Y = 7n Now, let check first option (X² + Y²) is divisible by 7 ∴ (X² + Y²) = ((7m)² + (7n)²) = 49 (m² + n²), which is divisible by 7 Now, let check second option (X² - Y²) is divisible by 7 ∴ (X² - Y²) = ((7m)² - (7n)²) = 49 (m² - n²), which is divisible by 7 Now, let check third option (X + Y) is divisible by 14 ∴ (X + Y) = ((7m) + (7n)) = 7 (m + n), which is divisible by 7 but not necessarily by 14 So, option third is incorrect Hence, option (3) is correct

If X and Y are two multiples of 7 then which of the following statement is incorrect?1. (X2 + Y2) is divisible by 72. (X2 - Y2) is divisible by 73. (X + Y) is divisible by 144. None of these

Answer» Correct Answer - Option 3 : (X + Y) is divisible by 14

Given:

X and Y is multiple of 7

Concept Used:

If the number is a multiple of given number then the number is also divisible by the given number

Calculation:

It is given in the question that X and Y are multiples of 7

∴ X = 7m and Y = 7n

Now, let check first option (X² + Y²) is divisible by 7

∴ (X² + Y²) = ((7m)² + (7n)²) = 49 (m² + n²), which is divisible by 7

Now, let check second option (X² - Y²) is divisible by 7

∴ (X² - Y²) = ((7m)² - (7n)²) = 49 (m² - n²), which is divisible by 7

Now, let check third option (X + Y) is divisible by 14

∴ (X + Y) = ((7m) + (7n)) = 7 (m + n), which is divisible by 7 but not necessarily by 14