Final answer:
The fraction of Johnny's check that has been spent before he receives it is 8/17.
Step-by-step explanation:
To find the fraction of Johnny's check that has been spent before he receives it, we need to calculate the total amount deducted from his earnings in proportion to his total earnings.
First, we subtract the insurance payment of $100 from his weekly earnings of $850, which leaves us with $750.
Then, we calculate the tax deduction by multiplying $750 by 0.08 (8%). This gives us a tax deduction of $60.
So, the total amount deducted from Johnny's earnings is $100 (insurance) + $60 (tax), which equals $160.
To find the fraction of his check that has been spent, we divide the total deduction by his earnings: $160/$850.
Simplifying this fraction gives us 8/17.