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Question

Find the next term.
64, 32, 48, 120, 420, ______

The correct answer is
1890

Sequence Pattern Analysis

The question asks us to find the next term in the given number sequence: 64, 32, 48, 120, 420, ______. To solve this, we need to identify the pattern or rule that governs the progression of numbers in the sequence.

Step-by-Step Calculation

Let's examine the relationship between consecutive terms by looking at the multiplier needed to get from one term to the next:

  • From the first term (64) to the second term (32): The multiplier is $\frac{32}{64} = 0.5$ or $\frac{1}{2}$. $64 \times \frac{1}{2} = 32$
  • From the second term (32) to the third term (48): The multiplier is $\frac{48}{32} = 1.5$ or $\frac{3}{2}$. $32 \times \frac{3}{2} = 48$
  • From the third term (48) to the fourth term (120): The multiplier is $\frac{120}{48} = 2.5$ or $\frac{5}{2}$. $48 \times \frac{5}{2} = 120$
  • From the fourth term (120) to the fifth term (420): The multiplier is $\frac{420}{120} = 3.5$ or $\frac{7}{2}$. $120 \times \frac{7}{2} = 420$

Observing the sequence of multipliers (0.5, 1.5, 2.5, 3.5), we can see a clear pattern. Each multiplier is exactly 1 greater than the previous one. The multipliers can be written as fractions with a denominator of 2:

  • First multiplier: $\frac{1}{2}$
  • Second multiplier: $\frac{3}{2}$
  • Third multiplier: $\frac{5}{2}$
  • Fourth multiplier: $\frac{7}{2}$

The numerators (1, 3, 5, 7) are consecutive odd numbers. The sequence of multipliers is $\frac{1}{2}, \frac{3}{2}, \frac{5}{2}, \frac{7}{2}$.

Determining the Next Term

Following this identified pattern, the next multiplier should be derived from the next odd number, which is 9. So, the next multiplier will be $\frac{9}{2}$, which is equal to 4.5.

To find the next term in the sequence, we multiply the last given term (420) by this next multiplier (4.5):

Next Term $= 420 \times 4.5$

Let's perform the calculation:

Next Term $= 420 \times \frac{9}{2}$

Next Term $= (\frac{420}{2}) \times 9$

Next Term $= 210 \times 9$

Next Term $= 1890$

Therefore, the next term in the sequence 64, 32, 48, 120, 420, is 1890.

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Important Questions from Number Series

  1. What will come in place of question mark (?) in the following number series?

    2, 5, 11, 23, 44, 77, ?

  2. What will come in place of question mark (?) in the following number series?

    31, 32, 36, ?, 61, 86

  3. What will come in the place of question mark (?) in the following number series?

    3, 6, 18, ?, 630, 6930

  4. What should come in place of the question mark ‘?’ in the following number series?

    60, 40, 50, ?, 180, 460

  5. A series is given with one term wrong. Select that wrong term from the given alternatives.

    J12, M24, P48, S96, U192

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