If S = (4t + 3)(t - 2), find ds/dt when t = 5 secs.
A
50 units per sec
B
35 units per sec
C
22 units per sec
D
13 units per sec
Verified Correct Answer: B.
Step-by-Step Mathematical Solution
\(s = (4t + 3)(t - 2)\)
\(\frac{\mathrm d s}{\mathrm d t} = (4t + 3)(1) + (t - 2)(4)\)
= \(4t + 3 + 4t - 8\)
= 8t - 5
\(\frac{\mathrm d s}{\mathrm d t} (t = 5 secs) = 8(5) - 5\)
= 40 - 5
= 35 units per sec
Source: Myschool Past Questions Archive (Record #55079)