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Bob just filled his car's gas tank with 20 gallons of gasohol, a mixture consisting of 5% ethanol and 95%
gasoline. If his car runs best on a mixture consisting of 10% ethanol and 90% gasoline, how many gallons of
ethanol must he add into the gas tank for his car to achieve optimum performance?
  • a)
    9/10
  • b)
    1
  • c)
    10/9
  • d)
    20/19
  • e)
    2
Correct answer is option 'C'. Can you explain this answer?
Verified Answer
Bob just filled his car's gas tank with 20 gallons of gasohol, a m...
Bob put 20 gallons of gasohol into his car's gas tank, consisting of 5% ethanol and 95% gasoline. Chemical Mixture questions can be solved by using a mixture chart. 
This chart indicates that there is 1 gallon of ethanol out of the full 20 gallons, since 5% of 20 gallons is 1 gallon.
Now we want to add x gallons of ethanol to raise it to a 10% ethanol mixture. We can use another mixture chart to represent the altered solution.

Therefore, the following equation can be used to solve for x:

The correct answer is C.
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Most Upvoted Answer
Bob just filled his car's gas tank with 20 gallons of gasohol, a m...
The first step to solving this problem is to determine how much ethanol is currently in the gas tank. We are given that Bob filled his car's gas tank with 20 gallons of gasohol, which is a mixture consisting of 5% ethanol and 95% gasoline.

To find the amount of ethanol in the 20 gallons of gasohol, we can use the formula:

Ethanol content = Total volume x Ethanol percentage

Plugging in the values, we have:
Ethanol content = 20 gallons x 5% = 1 gallon

So, Bob currently has 1 gallon of ethanol in his gas tank.

The second step is to determine how much ethanol Bob needs to add in order to achieve the optimum performance for his car, which is a mixture consisting of 10% ethanol and 90% gasoline.

Let's assume that Bob needs to add x gallons of ethanol to the gas tank.

The total volume of the gas tank after adding x gallons of ethanol would be 20 + x gallons, and the ethanol content would be 1 + x gallons.

Using the formula for ethanol content, we can set up the following equation:

Ethanol content = Total volume x Ethanol percentage

(1 + x) gallons = (20 + x) gallons x 10%

Simplifying the equation, we have:
1 + x = (20 + x) x 10/100
1 + x = (20 + x) / 10
10(1 + x) = 20 + x
10 + 10x = 20 + x
9x = 20 - 10
9x = 10
x = 10/9

Therefore, Bob needs to add 10/9 gallons of ethanol into the gas tank in order to achieve optimum performance.
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Bob just filled his car's gas tank with 20 gallons of gasohol, a mixture consisting of 5% ethanol and 95%gasoline. If his car runs best on a mixture consisting of 10% ethanol and 90% gasoline, how many gallons ofethanol must he add into the gas tank for his car to achieve optimum performance?a)9/10b)1c)10/9d)20/19e)2Correct answer is option 'C'. Can you explain this answer?
Question Description
Bob just filled his car's gas tank with 20 gallons of gasohol, a mixture consisting of 5% ethanol and 95%gasoline. If his car runs best on a mixture consisting of 10% ethanol and 90% gasoline, how many gallons ofethanol must he add into the gas tank for his car to achieve optimum performance?a)9/10b)1c)10/9d)20/19e)2Correct answer is option 'C'. Can you explain this answer? for UPSC 2024 is part of UPSC preparation. The Question and answers have been prepared according to the UPSC exam syllabus. Information about Bob just filled his car's gas tank with 20 gallons of gasohol, a mixture consisting of 5% ethanol and 95%gasoline. If his car runs best on a mixture consisting of 10% ethanol and 90% gasoline, how many gallons ofethanol must he add into the gas tank for his car to achieve optimum performance?a)9/10b)1c)10/9d)20/19e)2Correct answer is option 'C'. Can you explain this answer? covers all topics & solutions for UPSC 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for Bob just filled his car's gas tank with 20 gallons of gasohol, a mixture consisting of 5% ethanol and 95%gasoline. If his car runs best on a mixture consisting of 10% ethanol and 90% gasoline, how many gallons ofethanol must he add into the gas tank for his car to achieve optimum performance?a)9/10b)1c)10/9d)20/19e)2Correct answer is option 'C'. Can you explain this answer?.
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