Jenny is incorrect in her calculation.
For every time that Jenny's brother washed dishes, Jenny washed dishes 4 times. This tells that the the times they washed dishes occur in the ratio 4 :1. If Jenny's brother washed dishes 8 times, Jenny has to have washed dishes [tex]4\times 8=32[/tex] times. The way Jenny's is doing the calculation implies that his brother washed dishes [tex]3*\times 8 =24[/tex] times. He calculation yields a wrong result.
