<span>85% ethanol | 25% ethanol | 50% ethanol
x | y | 20 gal
use x and y because you don;t know how much she needs.
0.85x | 0.25y | 20(0.5)
85% is 85/100 or 0.85, and you need that much of x, same goes for the 25% and 50% mixtures so now you can make up 2 equations
1) x + y = 20 2) 0.85x + 0.25y= 10 (you get 10 when you multiply 20 by 0.5) now you can solve for x or y using substitution.
first rewrite 1) in terms of x or y: x+ y= 20 ----> y= 20 - x now you can substitute 20- x for y in the second equation.. 0.85x + 0.25y= 10 0.85x + 0.25(20-x)= 10 distribute here..(0.25 * 20 and 0.25 * (-x) ) 0.85x + 5 - 0.25x = 10 combine like terms 0.6x +5 = 10 move the 5 over to the other side 0.6x= 10 -5 0.6x = 5 divide both sides by 0.6 x= 25/3 or 8.3 now you know the amount of x so you can substitue this back into the first equation to find y. 0.85x + 0.25y= 10 0.85(25/3) +0.25y= 10 85/12 + 0.25y= 10 0.25y = 10- 85/12 0.25y= 35/12 y= 35/3 or 11.6 you can check by putting these values into the euations: 1) x+ y= 20 25/3 + 35/3 =20 20= 20 good so far 2) 0.85x + 0.25y= 10 0.85(25/3) + 0.25(35/3)=10 10 = 10
so our values for x and y work
x= 25/3 and y= 35/3</span>
Stoms or tornadoes cause about ten times more damage a year, on average, as hurricanes. Storms often cause more complete destruction than hurricanes because of their large size, long-term duration, and their varied potential for damage to property.
Storms can be very severe storms, hurricanes often last a long time, cover most of the earth and cause great damage. The wind from the strongest calves is stronger than the one from the strongest storms.
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Answer:
1. They are found in nearly limitless supply.
Renewable resources are those which are abundantly present in nature and can be replenished again after single use. For example water, air and sunlight.
2. increased
Over the past 100 years, the amount of fossil fuel consumption has increased because with the increase in the population cover all over the world, the requirement of fossil fuels is also increasing. Fossil fuels are required for the generation of thermal and electrical energy.
3. United States
The United States is the reservoir of coal. It is a chief exporter of the coal to India, Netherlands , Japan, South Korea and Brazil.
There are two big advantages of using molarity to express concentration. The first advantage is that it's easy and convenient to use because the solute may be measured in grams, converted into moles, and mixed with a volume.
The second advantage is that the sum of the molar concentrations is the total molar concentration. This permits calculations of density and ionic strength
the answer should be letter B because the killer whales eat the fish which makes the population decrease, but if there were no killer whales, the fish population would go up
