(6-2.7h)+(-1.3j-4) find the sum

Jacob signs up to work for 2 1/2 hours at the school carnival. if each work shift is 3/4 hour, how many shifts will jacob work? (i just want to double check : |, for anybody that responds! : )

Awindow washer cleans 42 windows in 2 hours. at this rate, how many windows did he clean in 180 minutes.

*segment an is an altitude of right ? abc with a right angle at a. if ab = 2root 5 in and nc = 1 in, find bn, an, ac.