All Exams Test series for 1 year @ ₹349 only
Question

Fill in the blank: 1, 2, 6, 24, 120, ____

The correct answer is
720

Number Sequence Pattern Identification

The question asks us to find the missing number in the sequence: 1, 2, 6, 24, 120, ____. We need to identify the pattern governing this sequence to determine the next term.

Analyzing the Sequence Terms

Let's look at the given numbers:

  • Term 1: 1
  • Term 2: 2
  • Term 3: 6
  • Term 4: 24
  • Term 5: 120

Finding the Pattern Rule

We can examine the relationship between consecutive terms:

  • Term 2 from Term 1: $1 \times 2 = 2$
  • Term 3 from Term 2: $2 \times 3 = 6$
  • Term 4 from Term 3: $6 \times 4 = 24$
  • Term 5 from Term 4: $24 \times 5 = 120$

The pattern observed is that each term is generated by multiplying the previous term by an integer, and this integer increases by 1 for each subsequent step (multiplying by 2, then 3, then 4, then 5).

This sequence is also recognizable as the sequence of factorials:

  • $1! = 1$
  • $2! = 2 \times 1 = 2$
  • $3! = 3 \times 2 \times 1 = 6$
  • $4! = 4 \times 3 \times 2 \times 1 = 24$
  • $5! = 5 \times 4 \times 3 \times 2 \times 1 = 120$

Calculating the Missing Term

Following the identified pattern, the next multiplier should be 6.

We multiply the last term (120) by 6:

Calculation: $120 \times 6 = 720$

Alternatively, using the factorial pattern, the next term is $6!$:

Calculation: $6! = 6 \times 5 \times 4 \times 3 \times 2 \times 1 = 720$

Therefore, the missing number in the sequence is 720.

Was this answer helpful?

Important Questions from Sequence & Series

  1. 4 is related to 64 following a certain logic. Following the same logic, 9 is related to 729. To which of the following is 12 related following the same logic?
    (NOTE: Operations should be performed on whole numbers without breaking down the numbers into their constituent digits. E.g., 13 – Operations on 13 such as adding/multiplying, etc., to 13 can be performed. Breaking down 13 into 1 and 3 and then performing mathematical operations on 1 and 3 is not allowed.)

  2. What should come in place of ? in the given series based on the English alphabetical order?

    ACE, FHJ, KMO, PRT, ?

  3. Which of the following numbers will replace the question mark (?) in the given series? 

    3, 17, 83, 329, ?, 1961

  4. Two sets of numbers are given below. In each set of numbers, certain mathematical operation(s) on the first number result(s) in the second number. Similarly, certain mathematical operation(s) on the second number result(s) in the third number and so on. Which of the given options follows the same set of operations as in the given sets? (NOTE: Operations should be performed on the whole numbers, without breaking down the numbers into their constituent digits. E.g. 13 – Operations on 13 such as adding/subtracting/multiplying to 13 can be performed. Breaking down 13 into 1 and 3 and then performing mathematical operations on 1 and 3 is not allowed.)

  5. Find the area (in cm²) of the sector, where the radius of the circle is 24 cm and length of the arc is 7 cm.

Need Expert Advice?

Start Your Preparation with Prepp Mobile App

Download the app from Google Play & App Store
Download the app from Google Play & App Store
Prepp Mobile App