Dorothy types 120 words per minute. How many words does Dorothy type in 1.75 minutes?

210 words.

Firstly note that ##1.75=1 3/4## as a mixed number.

and that ##1 3/4=7/4" as an improper fraction."##

##rArr(120" words")/(1"min")=(x" words")/(7/4"min")##

and ##color(blue)"cross-multiplying"## gives.

##x=120xx7/4=cancel(120)^(30)xx7/cancel(4)^1=30xx7##

##=210" words"##