#1#. If Malik needs #30# minutes to drive to the airport from his home and needs to be at the airport #2# hours prior to departure, then start by calculating the total amount of time he needs to get ready for departure.
#2color(white)(i)"hours"+30color(white)(i)"minutes"#
#=2:30#
#2#. Subtract #color(blue)2:color(darkorange)30# from #color(red)7:color(teal)15#. Start by subtracting the hours first.
#color(red)7color(white)(i)"hours"-color(blue)2color(white)(i)"hours"#
#=color(brown)(5color(white)(i)"hours")#
#3#. Subtract the minutes.
#color(teal)15color(white)(i)"minutes"-color(darkorange)30color(white)(i)"minutes"#
#=color(violet)(-15color(white)(i)"minutes")#
#4#. Since #-15color(white)(i)"minutes"# is negative, this means #15# minutes is subtracted from #5color(white)(i)"hours"#. Thus, subtact #15color(white)(i)"minutes"# from #5color(white)(i)"hours"#.
#color(brown)(5color(white)(i)"hours")# #color(violet)(-15color(white)(i)"minutes")#
#=color(green)(|bar(ul(color(white)(a/a)4:45color(white)(a/a)|)))#
#:.#, Malik should leave his house at #4:45# P.M.
