David W. answered 10/11/17
Tutor
4.7
(90)
Experienced Prof
"28yr to 36 yr"
28 yr : 36 yr [written as a ratio]
(28 yr) / (36 yr) [written as a fraction]
28 / 36 [cancel yr]
7/9 [divide both numerator and denominator by 4 to get simplest form]