Tutor profile: Neha A.
Subject: SAT II Mathematics Level 2
If f(x)=(15x+1)/(14x+2), what value does f(x) when x reaches infinity?
Since x is becoming infinitely larger, we can assume that 1 in 15x+1 in the numerator is insignificant and 2 in 14x+2 in the denominator is insignificant. If they are insignificant, we can pretend that they do not exist. So f (x) = 15x/14x. Since x is both in the numerator and denominator, we can cancel out x, and we are left with 15/14 which is the value of f (x) when x reaches infinity.
Is the head of of a phospholipid hydrophilic or hydrophobic?
It is hydrophilic, which means it is polar and is water-soluble, and that is why it faces the cytoplasm and the outside of a cell. Hydrophobic means that it is non-polar and repels water.
If Fred, who works at a restaurant, makes 15 dollars an hour, and receives 2 dollars in tips for every meal he serves, how many hours does he need to work to make 115 dollars in total while serving 20 meals?
We will assign variables x to the number of hours he needs to work. Since we know he makes 2 dollars in tips for every meal he serves and he served 20 meals, we can multiple 2 and 20 together to get 40 dollars. That is how much he made in tips. The equation we now have is 15x+40=115, and x= the number of hours he works. We first subtract 40 from 115. The equation we now have is 15x=75. We divide 75 by 15 to get x = 5. The answer is 5, and Fred needs to work 5 hours to make 115 dollars in total.
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