Answer:
21%
Step-by-step explanation:
Formula for this type of problem is
[tex]\frac{84}{400} = \frac{x}{100}[/tex]
cross multiply
[tex]8400 = 400x[/tex]
divide by 400
[tex]8400 = 400x[/tex]
/400 /400
[tex]21 = x\\[/tex]
plug 21 into the original equation
[tex]\frac{84}{400} = \frac{21}{100}[/tex]
simplify
[tex]\frac{84}{100} = .21[/tex]
.21 can be represented as 21%