Let x = mileage
98 >= 35 + .21x
Solving for x:
98 >= 35 + .21x
63 >= .21x
300 >= x
.
This says that if the total mileage is 300 miles or less he will be within his budget.
f(x)=40
x=8
so if x=2 it would be 40/8 which is 5
50 minutes= 5/6 hr
(1 3/4 miles)/ (5/6 hr)= 2.1 miles/hr
Hope this would help~
I think the answer is option 3.
Suppose:
C=cost
c=cost per kilo-watt hour
w=number of watts
h=number of hours
thus
C=kwhc
where:
k=constant of proportionality:
k=C/(whc)
but
C=15 when w=6000, h=10/60=1/6 hours, c=7.5 cents per kw/h
thus
k=15/(6000*1/6*7.5)
k=0.002
thus:
C=0.002(whc)
hence:
when
h=70*2=140=140/6=70/3 hours the cost will be:
C=0.002(6000*70/3*7.5)
C=2100 cents
C=$21
