well, if they mowed for 12 hours, they would cut 3+4=7 lawns.
rate=7lawns/12 hours
1lawn=rate*time=7/12 lawns/hr*time
time= 12/7 hrs or 1 5/7 hr
rate=7lawns/12 hours
1lawn=rate*time=7/12 lawns/hr*time
time= 12/7 hrs or 1 5/7 hr
1/.583 is 1.715hr
John should just go home and let maria do it all.
First, let's find John's work rate. We know that it takes him 4 hours to mow the lawn, so in 1 hour, he can mow 1/4th of the lawn (1 lawn / 4 hours = 1/4th lawn/hour).
Next, let's find Maria's work rate. We are given that it takes her 3 hours to mow the same lawn, so in 1 hour, she can mow 1/3rd of the lawn (1 lawn / 3 hours = 1/3rd lawn/hour).
To find their combined work rate, we simply add their individual work rates. So, John and Maria together can mow (1/4th + 1/3rd) of the lawn in 1 hour.
To simplify this fraction, we need a common denominator, which is 12. So, the combined work rate is (3/12 + 4/12) = 7/12th of the lawn/hour.
Finally, to find the time it would take for John and Maria to mow the lawn together, we divide the amount of work (1 lawn) by their combined work rate (7/12th lawn/hour).
(1 lawn) / (7/12th lawn/hour) = 12/7 hours
Therefore, it would take John and Maria approximately 12/7 hours or approximately 1.71 hours to mow the lawn together.