This is esay to do when you realize the the speed of mowing is addtive. This is if John mows at 1 lawn / (2/3) hour and Gerge mows at 1 lawn / 1hour, the total speed of mowing is:
1 / (2/3) + 1 = 3/2 + 1 = 5/2
=> 5/2 of lawn per hour
Now, the time is calcualted as the amount of lawn divided by the speed:
1 lawn / (5/2 lawn/hour) = 2/5 hour.
Answer: 2/5 of an hour.
When it is in () it means multiply x=45
Answer:
Step-by-step explanation:
The answer is actually
Let:
S=1+2+3+4+5+6+7+8+9+n
We know the answer to the following infinite sum:
S2=1-1+1-1+1-1+1-1+1-1+1-1+1-....= - 1/2
We can therefore solve for this sum:
S3=1-2+3-4+5-6+7-8+9-....
We add them:
S3= 1-2+3-4+5-6+7-8...
S3= +1-2+3-4+5-6+7-8...
________________
2S3= 1-1+1-1+1-1+1-1+1-....
Therefore:
2S3=S2=
