Pick the odd one out in the following: 13, 23, 33, 43, 53
33
Sequence Analysis: Find the Odd Number Out
This question asks us to identify the number that does not follow the pattern established by the other numbers in the given sequence: 13, 23, 33, 43, 53.
Number Properties Analysis
To find the odd one out, let's examine the properties of each number in the list:
- 13: This is a prime number. It is only divisible by 1 and itself. The sum of its digits is $1 + 3 = 4$.
- 23: This is a prime number. It is only divisible by 1 and itself. The sum of its digits is $2 + 3 = 5$.
- 33: This is a composite number. It is divisible by 1, 3, 11, and 33. The sum of its digits is $3 + 3 = 6$.
- 43: This is a prime number. It is only divisible by 1 and itself. The sum of its digits is $4 + 3 = 7$.
- 53: This is a prime number. It is only divisible by 1 and itself. The sum of its digits is $5 + 3 = 8$.
Odd Number Conclusion
Observing the properties:
- Most numbers in the sequence (13, 23, 43, 53) are prime numbers.
- The number 33 is the only composite number in the sequence.
- Alternatively, we can consider divisibility by 3. A number is divisible by 3 if the sum of its digits is divisible by 3.
- For 13, the sum is 4 (not divisible by 3).
- For 23, the sum is 5 (not divisible by 3).
- For 33, the sum is 6 (divisible by 3).
- For 43, the sum is 7 (not divisible by 3).
- For 53, the sum is 8 (not divisible by 3).
Based on these observations, the number 33 stands out because it is the only composite number and the only one divisible by 3 in the given list. Therefore, 33 is the odd one out.
Important Questions from Numerical Reasoning
A traveller to the town reaches a crossroad. Upon asking residents A, B and C for directions to a certain destination, he gets the following responses
A: turn left
B: do not turn left
C: go straight
If only one among A, B and C is truthful, the traveller
In a city, each person has at least one hair on his/her head. At least two persons in this city are guaranteed to have exactly the same number of hair on their heads if the population of the city
a, b, c are real numbers. The quadratic equation ax2 – bx + c = 0 has equal roots, which is β, then
S, M, E and F are working in shifts in a team to finish a project. M works with twice the efficiency of others but for half as many days as E worked. S and M have 6 hour shifts in a day, whereas E and F have 12 hours shifts. What is the ratio of contribution of M to contribution of E in the project?
If x>y>1, which of the following must be true?
(i) In x > In y
(ii) ex > ey
(iii) y2 > x2
(iv) cos x > cos y
