p=paul's height
s=steve's height
t=theresa's height
p=s
1 and 1/2=3/2
1 and 1/3=4/3
p=-16+(3/2)t
s=-6+(4/3)t
p=s so
-16+(3/2)t=-6+(4/3)t
add 6 to both sides
-10+(3/2)t=(4/3)t
times both sides by 6 to clear fractions
-60+9t=8t
minus 9t both sides
-60=-t
times -1
60=t
t=60
theresa is 60 inches or 5ft
steve and paul are 84 inches or 7ft (wow!)