On selling 14 notebooks a seller makes a profit equal to the selling price of 9 notebooks. Find his percent profit (selling price of all notebooks is same. Cost price of all notebooks is same).

180%

S.P. of 14 note book - C.P. of 14 note book = S.P. of 9 note book

C.P. of 14 note book = S.P. of 5 note book

Let C.P. of each note book = 1 Rs.

Then C.P of 5 note book = 5 Rs.

S.P. of 5 note book = 14 Rs.

∴Profit = 14 − 5 = 9

Profit% = \(\frac{9 × 100}{5}\) = 180%