4.
7:6=walking:jogging
walking=7 units=14mins
divide by 7
1unit=2mins
toatl=7+6units=13units
1unit=2mins
times 13 both sides
13unit=total time=26mins
answer is 26mins
5.
a.
boys to girls=2:3
boys=24
2units=boys=24
divide by 2
1unit=12
girsls=3unit
12 times 3=36
girls=36
b.
80 students
3+2=5 units
80=5unit
divide by 5
16=1unit
girls=3unit
3 times 16=48 girls
c.
2+3=5
75=5 unit
divide by 5
15=1unit
girls=3unit
boys=2unit
girls-boys=3-2unit=1unit
1unit=15
15 more girsl than boys