GATE Mechanical 2024 | GA | Question: 2

Question

​​​Find the odd one out in the set: $\{19,37,21,17,23,29,31,11\}$

• A. $21$
• B. $29$
• C. $37$
• D. $23$

Answer 1

Correct answer is Option A)

remaining all are Prime numbers, just 21 is not prime, factors are 1,3,7,21.

Answer 2

21 is the odd one in the set as all other numbers 19,37,17,23,19,31,11 are prime numbers . Which means all the numbers except 21 has only two divisors, 1 and that number itself. But 21=7x3 which means 21 is a composite number and has 4 divisors (1,3,7,21).

Answer 3

FROM THE ABOVE CONDITION....

• EXCEPT 21, ALL NUMBER ARE PRIME NUMBER 

          

SO, CORRECT ANSWER IS OPTION (A)

Answer 4

A

Answer 5

A

remaining all are Prime numbers, just 21 is not prime, factors are 1,3,7,21.