Answer:
A) We know that she make $7 per hour, with this we can make a table:
1hr | $7
2hr | $14
3hr | $21
etc...
B) If in one week she earns $105 and 1w = 7h (1hr = $7) holds true, that means that we have to divide 105 by 7 which gives us 15hrs
C) If she baby-sat for 24hrs, we just have to multiply that by 7 and we get $168
Hope that helped!