Question

In the following number series, only one number is wrong, find out the wrong number 888, 454, 237, 128.5, 76.25, 47.125

• A. 76.25
• B. 454
• C. 128.5
• D. 237

Answer 1

The Correct Option is A

To determine the incorrect number within the series 888, 454, 237, 128.5, 76.25, 47.125, we must first identify the logical pattern followed by the correct sequence.

Let's analyze the given series: 

1. The sequence seems to be decreasing. Analyzing the ratios between the consecutive terms can help identify the pattern:
2. Divide each number by the next one in sequence to see if a consistent ratio emerges:

Terms	Calculation	Ratio
888 to 454	\(\frac{888}{454} \approx 1.956\)	Approximately 2
454 to 237	\(\frac{454}{237} \approx 1.916\)	Approximately 2
237 to 128.5	\(\frac{237}{128.5} \approx 1.844\)	Approximately 2
128.5 to 76.25	\(\frac{128.5}{76.25} \approx 1.685\)	Approximately 1.7
76.25 to 47.125	\(\frac{76.25}{47.125} \approx 1.619\)	Approximately 1.6

It appears that the ratio between 128.5 and 76.25 deviates significantly from the approximate ratio of 2 followed in earlier pairs, suggesting this might be the incorrect number. To confirm:

If we replace 76.25 with what it should be by maintaining the approximate ratio of 2:

• \(128.5 \div 2 = 64.25\)

Hence, the number 76.25 should be replaced with 64.25 to maintain the consistent ratio.

Therefore, the incorrect number in the sequence is 76.25.

Answer 2

The given series is:

888, 454, 237, 128.5, 76.25, 47.125

Step 1: Check the Pattern

We observe that each number in the series should roughly be half of the previous number. Let's check:

• 888 to 454: 888 ÷ 2 = 444 (but the next number is 454, not exactly half).
• 454 to 237: 454 ÷ 2 = 227 (but the next number is 237, not exactly half).
• 237 to 128.5: 237 ÷ 2 = 118.5 (but the next number is 128.5, not exactly half).
• 128.5 to 76.25: 128.5 ÷ 2 = 64.25 (but the next number is 76.25, which is too large).
• 76.25 to 47.125: 76.25 ÷ 2 = 38.125 (but the next number is 47.125, which is too large).

Step 2: Identify the Wrong Number

As we can see, the pattern of halving is disrupted at the number 76.25.

The expected value after 128.5 should have been 64.25, but the actual value is 76.25, which is too large.

Conclusion

The wrong number in the series is 76.25.