JEE Mains · Maths · STD 11 - 8. sequence and series
A software company sets up \(m\) number of computer systems to finish an assignment in \(17\) days. If \(4\) computer systems crashed on the start of the second day, \(4\) more computer systems crashed on the start of the third day and so on, then it took \(8\) more days to finish the assignment. The value of \(m\) is equal to :
- A \(125\)
- B \(150\)
- C \(180\)
- D \(160\)
Answer & Solution
Correct Answer
(B) \(150\)
Step-by-step Solution
Detailed explanation
\( 17 \mathrm{~m}=\mathrm{m}+(\mathrm{m}-4)+(\mathrm{m}-4 \times 2) \ldots+\ldots(\mathrm{m}-4 \times 24) \) \( 17 \mathrm{~m}=25 \mathrm{~m}-4(1+2 \ldots 24) \) \( 8 \mathrm{~m}=\frac{4 \cdot 24 \cdot 25}{2}=150\)
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