A series is given with one term missing. Choose the correct alternative from the given ones that will complete the series.
5,7.5,12.5,22.5,?
- A42.5
- B42
- C44
- D43.5
Solution & Step-by-step Explanation
Let's find the differences between the consecutive terms in the series:
7.5−5=2.5
12.5−7.5=5
22.5−12.5=10
Notice that the differences (2.5,5,10) are doubling each time:
2.5×2=5
5×2=10
Therefore, the next difference value must be:
10×2=20
Adding this difference to the last term gives the missing value:
22.5+20=42.5
7.5−5=2.5
12.5−7.5=5
22.5−12.5=10
Notice that the differences (2.5,5,10) are doubling each time:
2.5×2=5
5×2=10
Therefore, the next difference value must be:
10×2=20
Adding this difference to the last term gives the missing value:
22.5+20=42.5