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# Interpreting linear functions — Harder example

Watch Sal work through a harder Interpreting linear functions problem.

## Want to join the conversation?

• couldn't khan cut the mistake in through .
• I almost find it comforting that a teacher might also make a mistake; as long as he corrects it in the end!
• At , how do we know what "15" stands for? This video had me confused. Why do we try to find the mystery unit? Do we treat "32" as we would the variable "x"?
• It's because the equation is Gallons = 15 - miles/32. If the miles equal zero, it means the tank is full. So the equation would be Gallons = 15 - 0/32. Gallons = 15 - 0. Therefore, a full tank of gas holds 15 gallons.
• The whole miles per gallon thingy is a bit confusing......... Can anybody explain further to me.....thanks
• Miles per gallon means a total number of miles you can travel using a certain amount of gallons of fuel. For example if your miles per gallon 5, that means, with 1 gallon of gas, you go 5 miles. So 5 miles per 1 gallon.
If your miles per gallon 20, that means, with 1 gallon of gas, you go 20 miles.
So 20 miles per 1 gallon.
Hope this helps.
• hi i am aware that the 3 rd option is very confusing. Let me explain. So basically a tank of gas may have the same units which are gallons but be careful here because when they mention a tank of gas, they always are talking about the value 15 gallons as default. Hence if you pick the third one , you will basically be saying that solution is( miles/15 gallons). Hope this helps
• math is insane
• i'm guaranteed to fail my upcoming SAT
• Don't be pessimistic. Just do your best, and let the outcome be the outcome. But make sure to do your best. Otherwise, you will most likely have regrets.
Just don't give up, and remember the SAT does not determine how you live the rest of your life.
• at why did he take the reciprocal of both sides?
• In order to isolate the "units", he must switch out the co-existing variable on the left side.
• In the question about the gas tank (Interpreting linear functions - Harder example), don't we have to say "Alice's car can travel 32 miles per gallon" instead of "to the gallon"? I'm not a fluent English speaker, but I don't recall hearing such a way to say it.