person(1) has YEAR_PERCENT_MORE% more money today than he(1) did this time last year. If person(1) has $YEAR_THIS today, how much money did he(1) make over this past year? (Round to the nearest cent, or hundredth of a dollar.)
round((YEAR_THIS - YEAR_LAST) * 100) / 100
Let x
be the amount of money that he(1) had last year.
x + YEAR_PERCENT_MORE / 100x = $YEAR_THIS
(100 + YEAR_PERCENT_MORE) / 100x = $YEAR_THIS
x = \frac{$YEAR_THIS}{(100 + YEAR_PERCENT_MORE) / 100}
x = $YEAR_LAST
(rounding to the nearest penny in this step)
So, he(1) had $YEAR_LAST last year, but we want to know how much he(1) has made over the past year!
\text{money made over the past year} = \text{amount of money today} - \text{amount of money last year}
\qquad =$YEAR_THIS-$YEAR_LAST
\qquad \approx $round((YEAR_THIS - YEAR_LAST) * 100) / 100
So, the answer is $round((YEAR_THIS - YEAR_LAST) * 100) / 100.
person(1) has $DOLLARS to spend at a store. The store currently has a sale where the sale price is PERCENT_OFF% off the marked price. What is the highest marked price that person(1) can afford? (Round to the nearest cent, or hundredth of a dollar.)
HIGHEST_PRICE
Let x
be the highest marked price that person(1) can afford.
x-(PERCENT_OFF/100)x = \text{sale price} = \text{amount person( 1 ) has to spend}
((100-PERCENT_OFF)/100)x = $DOLLARS
x = $HIGHEST_PRICE