The height of the flagpole is three fourths of the height of the school. The difference in their heights is 4.5 m. What's the height of the school? Choices for school's height: 18, 20, 24. Please show work

height of school --- s

height of pole --- p

p = (3/4)s

s - p = 4.5
s - (3/4)s = 4.5
(1/4)s = 4.5
s = 18