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
Can I see the picture it’s blurry
Answer:
She is going at the rate of 4.5 feet per second.
Step-by-step explanation:
Given:
The rate of walking is 90 yards per minute.
Now, to find the rate in feet per second.
1 yard = 3 foot.
1 minute = 60 seconds.
So, first we find the rate of walking per second in yard = 
Therefore by dividing we get =
Now, we find the rate of walking per second in feet = 
So, by multiplying we get = 
Therefore, she is going at the rate of 4.5 feet per second.