High School

Find the wrong number in the given sequence: 25, 36, 49, 81, 121, 169, 225.

A) 36
B) 49
C) 121
D) 169

Answer :

Final Answer:

The wrong number in the given sequence is 121. Thus option C is correct.

Explanation:

In this sequence, each number is a perfect square, starting from [tex]\(5^2 = 25\).[/tex] We can calculate the perfect squares of consecutive numbers to identify the pattern.

[tex]\(5^2 = 25\)[/tex]

[tex]\(6^2 = 36\)[/tex]

[tex]\(7^2 = 49\)[/tex]

[tex]\(8^2 = 64\)[/tex]

[tex]\(9^2 = 81\)[/tex]

[tex]\(11^2 = 121\)[/tex]

[tex]\(13^2 = 169\)[/tex]

[tex]\(15^2 = 225\)[/tex]

Upon closer inspection, it's evident that 121 is not the perfect square of any consecutive natural number in this sequence. The correct number should be [tex]\(10^2 = 100\).[/tex] Hence, option c) 121 is the wrong number in the sequence.

The given sequence follows a pattern of consecutive perfect squares. However, the number 121 does not fit this pattern. Instead, it seems to be a deviation, which suggests it is the incorrect number in the sequence. By calculating the perfect squares of consecutive numbers, we can clearly identify that the next perfect square after 81 should be 100, which corresponds to [tex]\(10^2[/tex]. Therefore, option c) 121 is the incorrect number.