Solution:Given:
The shopkeeper sells 20% less amount of an article
The markup% = 14.29%
Discount% = 10%
Formula used:
M.P = (C.P × (100 + markup%))/100%
S.P = (M.P × (100 - discount%))/100%
Discount% = [(M.P - S.P)/M.P] × 100%
Profit% = [(S.P - C.P)/C.P] × 100%
Where M.P = Marked price, S.P = Selling price, C.P = Cost price
Calculation:
Let the C.P be 700x
So, M.P will be = 700x × (1 + 1/7) = 800x (Here, we use the fractional value of 14.29% = 1/7)
⇒ 800x
Now, he gave a 10% discount
So, after the discount S.P will be = (800x × (100 - 10))/100 = 720x
According to the question, he sells 20% less than the original weight of the article
So, if he bought 100 units he sold only 80 units
So, the C.P of 80 units = (700x/100) × 80 = 560x
But, he sold it at Rs. 720x
So, profit% = [(720x - 560x)/560x] × 100%
= 28.57%