Jason is saving up for a skateboard and helmet. The skateboard is $45.50 with tax and the helmet is $18.25 with tax. He earned 1/3 of the money by mowing lawns and the rest by babysitting. How much did Jason earn babysitting?

A.
$19.13

B.
$21.25

C.
$30.33

D.
$42.50

The total cost of the skateboard and helmet is $45.50 + $18.25 = $<<45.50+18.25=63.75>>63.75.

Jason earned 1/3 of that amount by mowing lawns, so he earned $63.75 / 3 = $<<63.75/3=21.25>>21.25 babysitting. Answer: \boxed{B}.