Answer:
Assume x is directly proportional to y :

when y is 9, x is 2:
substitute to find value of k :

Therefore, equation is:

Answer:
$1255.
Step-by-step explanation:
Mark me brainlest!
Number 1 is A, number 2 is B number three is D
Answer:
A $0.02
Step-by-step explanation:
Let's solve how much does it cost to have a bulb on for an hour. ⇒ 120 watt = 0.1 kilowatt per hour which costs 0.20 per kilowatt per ⇒ 0.1 kilowatt per hour* 0.20 = 0.02 dollars in an hour.