Multiple choice

Directions: Given below is a sequence. 8, 7, 18, 85, 588, 5283 If 755313 is the nth term of the sequence, find the value of 'n'.

  1. 10

  2. 6

  3. 7

  4. 8

  5. 11
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The sequence follows the pattern: term(n) = term(n-1) * n + (n-1). For example: 8*1-1=7, 7*2+4=18, 18*4+13=85. This is a complex recursive pattern, and n=8 correctly yields the target value.

AI explanation

The series multiplies the previous term by an integer and then subtracts the same integer to get the next term. For example, 8 times 1 minus 1 equals 7, 7 times 2 minus 2 equals 12, and 12 times 3 minus 3 equals 33, which breaks the given sequence of 18, 85, and so on. Testing another pattern where 8 times 1 minus 1 is 7, then 7 times 3 minus 3 is 18, and 18 times 5 minus 5 is 85 shows the multiplier is consecutive odd numbers. Continuing this, 588 times 9 minus 9 is 5283, so the next multipliers are 11, 13, and 15, making the 8th term 755313. The value of n is 8.

Keep practicing — related questions