Question

Find the Odd one among: 10, 34, 130, 204, 290
A) 34
B) 74
C) 130
D) 204

Answer 1

Hint: In this question, to find the odd one out in the series we have to check which rule will be applied on each number of the series (using hit and trial method). Here we can notice that every number is a sum of the square of odd numbers. So, let’s check every given term in the series.

Complete step-by-step answer:
We have 10, 34, 130, 204, 290.
Now, we will try to check which number is odd one.
Here we notice that 10 $ = 1 + 9 = {1^2} + {3^2}$;
Now we will check for 34 $ = 9 + 25 = {3^2} + {5^2}$
Let’s check for 130$ = 49 + 81 = {7^2} + {9^2}$
Again 204 $ \ne {9^2} + {11^2} = 202$
Therefore, 204 is an odd one because the rest of the numbers are the sum of the squares of odd numbers except 204.
Hence, option (D) is correct.

Note: These types of questions can be only done by hit and trial method. The sequence of numbers in a certain order, and in which some numbers are placed wrongly in the series and some numbers are missing is called a number series. To solve the number series, we need to read the question carefully.Then we need to check the pattern of the series. Generally, three types of questions asked from number series- (1) A number in the series is wrongly placed. This type of question we have already solved above. (2) Series of missing numbers in which specific numbers would be missing, where you need to find the missing number. (3) Incomplete number series where you need to solve incomplete number series in the same way in which the complete number series is given.