2 x 8 =16
16 granola bars a week
52 x 16 = 832 granola bars in a year
B = hourly rate for babysitting and w = hourly rate for working at water park
3b + 10w = 109...multiply by -8
8b + 12w = 177...multiply by 3
----------------------
-24b - 80w = - 872 (result of multiplying by -8)
24b + 36w = 531 (result of multiplying by 3)
---------------------add
- 44w = - 341
w = -341/-44
w = 7.75 <=== hourly rate for working at water park
3b + 10w = 109
3b + 10(7.75) = 109
3b + 77.50 = 109
3b = 109 - 77.50
3b = 31.50
b = 31.50/3
b = 10.50 <== hourly rate for babysitting
An estimation of 0.7
though the actual answer is 0.713580247