Harry can rake the leaves in the yard 8 hours faster than his little brother Jimmy can.
<span>If they join to work together they can complete the job in 3 hours. </span>
<span>1/x + 1/(x - 8) = 1/3 </span>
<span>3(x - 8) + 3x = x(x - 8) </span>
<span>x^2 - 14x + 24 = 0 </span>
<span>(x - 12)(x - 2) = 0 </span>
<span>Solutions: </span>
<span>x = 2 </span>
<span>x = 12 </span>
<span>Jimmy can complete the job on his own in 12 hours.</span>
METHOD 1
f(3) = 20
f(4) = 30
f(5) = 42
f(6) = 56
rate of change
f(4)-f(3)=10
f(5)-f(4)=12
f(6)-f(5)=14
then the average of change is 10+12+14 /3 = 12
METHOD 2 --- faster
rate of change = f(6)-f(3) / 6-3
= (36+18+2)-(9+9+2) / 3
= 36/3 = 12
Answer:
4
Step-by-step explanation:
one person is deemed to drive and that person is fixed on the driver's seat no mater which arrangement.
we have now 2 more seats one adjacent to the driver and one rear (two combined).
so the total ways in which all five can be arranged is as follows.
driver, adjacent to him(1) and three back.
driver adjacent to him (different person) and three back.
see the driver is always fixed so we can ignore him.
thus we when driver set fixed , on two remaining seats (adjacent to driver and the back )there can be 4 different combinations.
All you need to do is simplify 5-8 and it doesn't simplify any more so your ratio would be 5 to 8
