Answer:
it will take 1095 seconds to wash 18 dishes using a pipelined approach
Step-by-step explanation:
Let represent the identity of those three people with :
A
B
C
Now; let the function assigned to those  the people be:
A = Rinse
B =Scrub with soap
C = Dry
For the first dish pipeline
A(RInse) = 15 seconds
B (Scrub with soap) = 30 seconds
A(RInse) = 15 seconds
C(Dry) = 15 seconds
The total time taken to complete one dish to wash = (15 +30+ Â 15+15)seconds = 75 seconds
However ; A cannot take the second dish for rinse until the first dish has not been rinse for the second time by A, Â A can only start rinse from the second dish when the first dish is at C for dry
SO; for the second dish:
B (Scrub with soap) = 30 seconds
A(RInse) = 15 seconds
C(Dry) = 15 seconds
B (Scrub with soap) = 30 seconds
A(RInse) = 15 seconds
C(Dry) = 15 seconds
Similiarly ; for the third dish
B (Scrub with soap) = 30 seconds
A(RInse) = 15 seconds
C(Dry) = 15 seconds
B (Scrub with soap) = 30 seconds
A(RInse) = 15 seconds
C(Dry) = 15 seconds
B (Scrub with soap) = 30 seconds
A(RInse) = 15 seconds
C(Dry) = 15 seconds
Therefore, the total time taken to was 18 dishes = time to wash the first dish + time remaining for 17 dishes
= 75 +(30+15+15)×17
= 1095 seconds
Hence, it will take 1095 seconds to wash 18 dishes using a pipelined approach
