The answser is ten thosand
Step-by-step explanation:
X=e+r/d
swap both sides
e+r/d=x
subtract e from both sides
e-e+r/d=x-e
r/d=x-e
multiply d to both sides
d×r/d=x-e×d
r=x-e×d
In order to solve a proportion you need to cross multiply, so you would do:
4x20 and 9xX and you would get...
9x=80
then divide by nine to get
x=8.8888888889
which is technically 8.9