Given that she earns $8.40 an hour for mowing then for 7 hours of mowing, the amount earned
= 7 * $8.40
=$58.80
Furthermore, given that she earns $7.90 for baby sitting for an hour
Hence for mowing for 7 hours and baby sitting for 1 hour, the total amount she will earn
= $58.80 + $7.90
= $66.70