Determine the number that should replace the question mark (?) in the following sequence.
131, 143, 157, 175, 201, ?
Correct Answer :
243
Solution :
The correct option is 243.
To find the missing number in the sequence, let's analyze the difference between consecutive terms:
First term: 131
Second term: 143
Third term: 157
Fourth term: 175
Fifth term: 201
Now, let's observe the sequence of first differences:
12, 14, 18, 26
Next, let's calculate the second differences (the differences between consecutive first differences):
The second differences are doubling at each step (2, 4, 8, ...), following powers of 2:
Following this pattern, the next second difference should be:
Adding 16 to the previous first difference (26) gives the next difference to add to 201:
Finally, add 42 to the last term (201) to find the missing number (?):
Thus, the number that replaces the question mark is 243.
Access expert-curated educational resources and study materials—completely free.
Create, conduct, and manage professional online assessments with Mindyard. Perfect for teachers and institutes.
Copyright © 2026 Mindyard. All Rights Reserved.