Using Amdahl's law, assume the sequential execution occurs in $15\%$ of the program, i$.$e$.$ other $85\%$ of the program can be parallelized with N processor with a speedup of N:

$($a$)$ What is the maximum overall speedup with an infinite number of processors?

$($b$)$ How many processors are required to be within $20\%$ of the maximum speedup?

$($c$)$ How many processors are required to be within $2\%$ of the maximum speedup?