Answer:
$30
Step-by-step explanation:
If $3 represents 10%, then multiply both numbers by 10 to get 100%
$3 = 0.1(x) ($3 is 10% of some value, 0.1 is 10% in decimal form)
$3(10) = 0.1(10)x
$30 = 1(x)
$30 = x (her allowance is $30)
