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If S = (4t + 3)(t - 2), find ds/dt when t = 5 secs.

If S = (4t + 3)(t - 2), find ds/dt when t = 5 secs.
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  • A 50 units per sec
  • B 35 units per sec
  • C 22 units per sec
  • D 13 units per sec
Correct Answer: Option B
Explanation:
\(s = (4t + 3)(t - 2)\)
\(\frac{\mathrm d s}{\mathrm d t} = (4t + 3)(1) + (t - 2)(4)\)
= \(4t + 3 + 4t - 8\)
= 8t - 5
\(\frac{\mathrm d s}{\mathrm d t} (t = 5 secs) = 8(5) - 5\)
= 40 - 5
= 35 units per sec

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