The table above shows the number of gallons of fuel used by two drivers, Mark and Daniel, during two different car trips on the same highway. If the two drivers have the same model cars
that get the same miles per gallon on the highway then, to the nearest mile, m, how many miles
was Daniel's trip?

for this case we have by definition, if two lines are perpendicular, then the product of their slopes is -1.

then, given the following line:

so,

we are looking for m_ {2}:

then, the line is given by:

we find "b" replacing the given point:

finally, the equation is:

option c

there is only one way to arrange all the eight relative to each other because they are not distinct. we have

now there are nine places to place an (and not more than one in one place).   because we have four symbols, we need to choose four of these nine places to insert an . order does not matter because the are not distinct.

thus there are 1 · c(9,4) ways, or, if we calculate it,

thus there are 126 ways to form such "words."