Question

If profit is equal to 75%,then CP = x profit amount​

Answer 1

Answer:

A person sold his watch for Rs 75. his profit percentage is equal to the cost of the watch. What is the cost price?

50+25=75

CP=P%=50

If you want to do this type of question without pen and paper then this method is for you, this method is applicable for all the questions in which profit percentage is equal to the cost price.

Trick: choose a number for profit% and add with by divide the same number by 10 and sqaureof that number .

10% =10+1

15%=15+2.25

20%=20+4

30%=30+9

50%=50+25

First see the example

Cp=10 P=10% SP=11 :: P=1 which is square of 1

CP=20 P=20% SP=24 :: P=4 which is a square of 2

CP=30 P=30% SP=39 :: P=9 which is a square of 3

CP=40 P=40% SP=56 :: P=16 which is a square of 4

…………….

…………..

…………

CP=90. P=90%. SP

Here profit = Sales Price(SP)-Cost Price(CP)

Now Profit = SP-CP = 75 -CP

Percentage profit = (Profit/CP)*100______________equation 1

Now Percentage profit = CP

So equation 1 will become

CP = {(75-CP)/CP} *100

here assume CP =X to solve the equation

X = {(75-X)/X}*100

X = (7500–100X)/X

X^2 =7500 - 100X

We will get a quadratic equation here,

X^2 + 100X - 7500 = 0

SOlving this equation will give 2 roots

X = - 150 and X = 50

Price could not be negative

SO X = 50 = Cost Price

Lets check in this equation

SP = 75 and CP =50

so profit = SP -CP =75–50 = 25

% profit = Profit/CP *100 = 25/50*100 = 50%____Correct as per question

Answer 2

Answer:

if traffic is equal to 75% then CP is equals to dash into profit amount