Answer:
the production function q exhibits decreasing returns to scale
Explanation:
to see if the function exhibits decreasing , increasing or constant returns of scale , let increase the input of the function
q=100L−20/k
then for N times units of Labor L and Capital K
qn =100(N*L)−20/(N*k) = N*[100*L - 20/(N²*K)]
since 20/(N²*K) < 20/K for N>1
qn =100(N*L)−20/(N*k) = N*[100*L - 20/(N²*K)] < N*[100*L - 20/(K)] = N*q (constant returns of scale )
thus qn < constant returns of scale
therefore q exhibits decreasing returns to scale