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Complete the series

90,85,75,55..???
a)20.
b) 25
C)15
D) 5 explain it plZzz answer is 25 but how???

User Nic
by
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1 Answer

2 votes

Answer:


\boxed{\text{C) 15}}

Explanation:

Let's examine the differences between consecutive terms


\begin{array}{cc}\textbf{Term} & \textbf{Diff.} \\90 & \\& 5 \\85 & \\& 10 \\75 & \\& 20 \\55 & \\& \mathbf{40} \\\mathbf{15} & \\\end{array}\\\text{The difference doubles with each consecutive term.}\\\text{If the pattern continues, the next term will decrease by 40.}\\\text{The next term in the series will be $\boxed{\mathbf{15}}$.}

User Navin Peiris
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