Select the number from among the given options that can replace the question mark (?) in the following series.
20,120,240,380,?
- A590
- B660
- C540
- D680
Solution & Step-by-step Explanation
Let's analyze the differences between consecutive terms:
120−20=100
240−120=120
380−240=140
Notice the pattern in the differences: the gaps are increasing by a constant value of +20 at each step (100,120,140).
Following this arithmetic progression, the next difference should be:
140+20=160
Therefore, the missing number is:
380+160=540
120−20=100
240−120=120
380−240=140
Notice the pattern in the differences: the gaps are increasing by a constant value of +20 at each step (100,120,140).
Following this arithmetic progression, the next difference should be:
140+20=160
Therefore, the missing number is:
380+160=540