Answer:
ai) 73000 gal/yr
aii) $730 per year
b) 1000 days
Step-by-step explanation:
ai) The water usage per day is ...
(4 showers/day)(10 min/shower)(5 gal/min) = 200 gal/day
Then the usage per year is ...
(200 gal/day)(365 days/yr) = 73,000 gal/yr
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aii) The cost of electricity is the cost of heating half the water usage, so is ...
(0.20 kWh/gal)(1/2)(73,000 gal/yr)($0.10/kWh) = $730/yr
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b) The current daily cost of electricity for heating water is ...
($730/yr)/(365 days/yr) = $2/day
If the cost is cut in half, it will be $1 per day. That means the savings is $1 per day, so it will take 1000 days to recover the $1000 initial cost. (Effectively, the average cost for the first 1000 days is the same as if the water heater had not been replaced.)
Step-by-step explanation:
sin(2x) = 2sin(x)cos(x)
2sin(x)cos(x) - cos(x) = 0
so one solution is cos(x) = 0.
=> x = pi/2 and 3pi/2 (90° and 270°)
for cos(x) <> 0 we have then
2sin(x) - 1 = 0
2sin(x) = 1
sin(x) = 1/2
=> x = pi/6 and 5pi/6 (30° and 150°)
Answer:
true
Step-by-step explanation:
all the sides match up. One side (the base) is shared which means they are the same length. The triangle at the top has a single hash on a side and so does the bottom one. This means they are the same length. The same thing occurs with the last remaining sides, they are congruent because they both have two hash lines. Since all three sides of both triangle add up, the triangles ARE CONGRUENT.
Answer:
5866
Step-by-step explanation:
Answer: 2/5 Step-by-step explanation: The easiest approach is to realize that one hour is 3 times longer than 20 minutes. The longer the time, the more they will pave.
