Answer:
x = 0
Step-by-step explanation:
if 2y + x = 4
we can assume that y = 2
if y - 3x = 2
it means 2 - 0 = 2
therefore x = 0
Answer:
2 pieces
Step-by-step explanation:
Given
Required
Calculate the number of pieces
To do this, we have to divide the length of the wood by the length of each piece.
Represent this with x
Convert mixed numbers to improper fraction
Change division to multiplication
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Answer:
(600 mi) × (5280 ft/mi) × (12 in/ft)
Step-by-step explanation:
A "unit multiplier" is a multiplier that has a value of 1. That is, the numerator and denominator have the same value. For units conversion problems, the numerator quantity has the units you want, and the denominator quantity has the units you're trying to cancel.
You have units of miles. You know that ...
1 mile = 5280 feet
1 foot = 12 inches
You want to get to units of inches. With these conversion factors, you can do it in two steps (as the problem requests). The first conversion is from miles to feet using the unit multiplier (5280 feet)/(1 mile). This gives you a number of feet.
Then the second conversion is from feet to inches, so you use the one that lets you put inches in the numerator and feet in the denominator:
(12 inches)/(1 foot)
When you multiplie these all out, units of miles and feet cancel, and you're left with inches.
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With the above conversion factors, you can write unit mulipliers of either ...
(5280 ft)/(1 mi) . . . to convert to feet
or
(1 mi)/(5280 ft) . . . to convert to miles.
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.)
