Answer:

Explanation:
We can use the formula shown below to solve this problem.
RWT = J
Where
R is the rate
W is the workers
T is the time
J is the number of jobs
First,
W = m
T = d
J = 1 [since it is said 1 job]
Lets find the Rate (R):
RWT = J
R(m)(d) = 1
R =

Now, using this value of R, we are going to find T, given:
W = n
J = 1/3
R = 1/md (found earlier)
So, let's find T:
RWT = J

This is the time it will take, in terms of d, m, and n