The answer would be D. an interval isnt a certain number but it is a time something happens over and over again
Answer:
5tyg5frhhu
Step-by-step explanation:
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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
Answer:
-1+3i
Step-by-step explanation:

Sqr root of 25 and 36 are 5 and 6 respectively
Sqr root of -25 and -4 are 5i and 2i respectively
Combine like with like
5-6=-1
5i-2i=3i
-1+3i
Notice the 7) 1st sequence, and the 8) second one