Each shot cost 20c.
She had 20 shots, so the total it cost her for shooting was 20 x 20c = $4.00
Since she only lost 70c, this means the amount she earned for hits was 4.00 - 0.70 = $3.30
Divide that amount by the amount she makes per hit:
3.30 / 0.30 = 11
She made 11 hits.
