Question

PROFIT AND LOSS:
Q 1: Raju bought a buffalo for rs. 10000 and a cow for rs. 7500. He sold the buffalo at a loss of 12% and the cow at a gain of 20%. Find his total gain or loss percent.
Q 2: By selling a watch for rs. 900, a man gains 20%. Find the C.P and Gain of the watch.
Q 3: A dealer loses 20%, if he sells an article for rs. 45. At what price should we sell the article, if he wants to gain 20%.
Q 4: By selling a book for rs. 132 a man gains 20%. What is the C.P of the book?

plzzzz help me answer these questions..... its very urgent frndz i have to submit it tomorrow itself please help me :(

Answer 1

These are the notations I'm gonna use,
Cost Price → P
Selling Price → P+∆P
Profit (or) Loss → ∆P
Relative Profit (or) Relative Loss → $\frac{\Delta P}{P}$

1. $P_{1}=10000, P_{2}=7500, \frac{\Delta P_{1}}{P_{1}}=-0.12, \frac{\Delta P_{2}}{P_{2}} = +0.20$
Hence, Net Gain (or) Net Loss is $\Delta P_{1}+\Delta P_{2}=(-0.12)(10000)+(+0.20)(7500)=300$.
Relative Net Gain$\frac{\Delta P_{1}+ \Delta P_{2}}{P_{1}+P_{2}}=\frac{(-0.12)(10000)+(+0.20)(7500)}{(10000)+(7500)} = 0.01714$.
Gain Percent is 1.714%.

2. $P+\Delta P=900, \frac{\Delta P}{P}=+0.20$
Hence, $P=750, \Delta P=+150$.
Cost Price is 750 and Profit is 150.

3. Let 'P' be the price of article, then $P+\Delta P_{o}=45, \frac{\Delta P_{o}}{P}=-0.20$.
Hence, Cost Price (P) is 56.25.
Now, $\frac{\Delta P}{P}=+0.20$.
Then Selling Price (P+∆P) is 67.5.

4. We have, $P+\Delta P =132, \frac{\Delta P}{P}=+0.20$.
Then, Cost Price (P) is 110.