Question

One year ago, a city's average rainfall for the month was r millimeters. The city's average rainfall, in millimeters, this month can be represented by the given expression.

0.45r

Which set of statements is true?
A.
The average rainfall for the month decreased by 45%.
An equivalent expression that represents this situation is r − 0.45r.
B.
The average rainfall for the month increased by 45%.
An equivalent expression that represents this situation is r + 0.45r.
C.
The average rainfall for the month increased by 55%.
An equivalent expression that represents this situation is r + 0.55r.
D.
The average rainfall for the month decreased by 55%.
An equivalent expression that represents this situation is r − 0.55r.

Answer 1

D.

0.45r = r − 0.55r, so the rainfall is 45% of last year (a decrease of 55%). The other choices give expressions that do not equal 0.45r.