Perl made the following conjecture.
the sum of a multiple of 4 and a multiple of 8 must be a multiple of 8.

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The answer is c because you turn 17.5% into a decimal which gives you .175 then you times that by $361.35 which gives you 63.23625 but then you round that which gives you 63.24. then you at 63.24 pulse 361.35 and you round it which gives you $425