Select the number from among the given options that can replace the question mark (?) in the following series: 30, 20, ?, 60, 140

Question

Accepted Answer

Let's analyze the series: 30, 20, ?, 60, 140.

Step 1: Look at the differences between the known terms.
- From 30 to 20, the difference is -10.
- From ? to 60, difference is unknown.
- From 60 to 140, difference is +80.

Step 2: Check if the differences form a pattern.
- Differences: -10, ?, +80

Step 3: Check the ratio or pattern in the numbers themselves.
- 30 to 20 is a decrease by 10.
- 20 to ? is unknown.
- ? to 60 is unknown.
- 60 to 140 is an increase by 80.

Step 4: Try to find a pattern in the series.
If we consider the series as:
30, 20, 30, 60, 140

Check differences:
- 30 to 20: -10
- 20 to 30: +10
- 30 to 60: +30
- 60 to 140: +80

The differences are: -10, +10, +30, +80

Step 5: The differences seem to be increasing: -10, +10, +30, +80
The pattern in differences could be roughly increasing by a factor or adding increasing amounts.

Step 6: Since 30 fits well and is one of the options, it is the most reasonable choice.

Therefore, the missing number is 30.

Answer

Answer

Answer