The marked price of 42 items was equal to the cost price of 70 items. The selling price of 25 items was equal to the marked price of 21 items. Calculate the percentage profit or loss from the sale of each item.

40% profit

Marked price of 42 items = Cost price of 70 items

\(\frac{MP}{CP}\) = \(\frac{10}{6}\)  ----- (1)

SP of 25 items = MP of 21 items

\(\frac{MP}{SP}\) = \(\frac{25}{21}\) -----(2)

Make MP same in both cases by multiplying with 5 in first and 2 in second equation=

CP                  MP                 SP

30                  50                  42

Profit = 42 - 30 = 12

Profit% = \(\frac{12 × 100}{30}\) = 40%