Answer:
The number of machines to complete job in 2 hours is 6.
Step-by-step explanation:
Using the relation of the rate of each one machine and knowing that adding up both rates.

Rate R =
'x' is the job
Rate S =
'x' is the job
So, using the equation of rates

Rate total is going to be a job in 2 hours so = 
<em>adding up</em>
<em>factoring the x</em>
<em>simplifying</em>
x= 
x= 6
Petri dish A has 1080000000000000
Petri dish B has 270000000000
Petri dish a is greater by 1.07973E15
Hope that helped :)
Answer:
hi so i think its a
Step-by-step explanation: