EXPLANATION:
To get the solution of the simultaneous equation, using the elimination method:
We will have the following steps:
Step 1:
Write the two equations:
Step2: Subtract the two equations:
Step 3: Simplify the expression
Step 4: Substitute x=-2 into the formula:
Therefore, the answer is
Thus,
Option B is correct
Answer:
18 Minutes
Step-by-step explanation:
Simon and sophie each do a fraction of the job per minute like this:
-Simon does per minute (if we multiply this by 30 we have the completed job)
-Sophie does of the job per minute (again if we multiply this by 45 we have the completed job)
We will add this two to know how much of the job they do together in a minute:
They will do of the job per minute.
So the total time will be when they do , we can put this in one equation like this:
where x is the total times we need to do of the job to complete it. We solve for x:
