Question

If it is given that y gallons were pumped into a storage tank, followed by addition of 50 gallons to the trailer, then calculate the initial total amount of gasoline in a fuel trailer, in gallons, if there are now x gallons.

• A. $x+y+50$
• B. $x+y-50$
• C. $y-x+50$
• D. $x-y-50$

Answer 1

Answer: (B)

$x+y-50$

Let the initial amount of gasoline in the trailer be $z$

Since $y$ gallons are pumped into a storage tank, the remaining gallons become $z-y$

$50$ gallons are added and the final amount is $x$.

$\Rightarrow z-y+50=x$

$\therefore z=x+y-50$