Question : Directions: In the following question, a series is given with one number missing. Select the missing number from the given alternatives.
1, 25, ?, 361, 841, 1681

Option 1: 169

Option 2: 225

Option 3: 161

Option 4: 121


Team Careers360 19th Jan, 2024
Answer (1)
Team Careers360 23rd Jan, 2024

Correct Answer: 121


Solution : Given:
1, 25, ?, 361, 841, 1681

Add the square root of the previous number to a consecutive even number starting from 4 and then square the resultant, to get the next number in the series –
(1) 2 = 1; (1 + 4) 2 = (5) 2 = 25; (5 + 6) 2 = (11) 2 = 121; (11 + 8) 2 = (19) 2 = 361; (19 + 10) 2 = (29) 2 = 841; (29 + 12) 2 = (41) 2 = 1681

So, the required number is 121. Hence, the fourth option is correct.

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