Answer
A is greater.
Work Step by Step
If B is 90% of A, then B is less than one whole part (100%) of A. This means A is greater.
For example, let A=100.
$90\%(A)=B\longrightarrow$ convert percent to decimal by moving decimal 2 places left.
$0.9A=B\longrightarrow$ substitute for A
$0.9(100)=B\longrightarrow$ multiply
$90=B$
$100\gt90$, so A is greater.
