If the profit per cent got on selling an article is numerically equal to its cost price in rupees and the selling price is Rs. 39, then cost price (in Rs.) will be:
A. 20
B. 22
C. 28
D. 30
Answer: Option D
Solution(By Examveda Team)
SP = Rs. 39 CP = x(let) Profit % = CP $${\text{or,}}\,\frac{{39 - x}}{x} \times 100 = x$$ $$\left[ {\% \,{\text{profit}} = \frac{{{\text{SP}} - {\text{CP}}}}{{{\text{CP}}}}} \right]$$$$\eqalign{ & 3900 - 100x = {x^2} \cr & {x^2} + 100 - 3900 = 0 \cr } $$
$$x=30$$ (we cannot take negative value of x)
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Comments ( 7 )
Related Questions on Profit and Loss
A. 45 : 56
B. 45 : 51
C. 47 : 56
D. 47 : 51
A. Rs. 2600
B. Rs. 2700
C. Rs. 2800
D. Rs. 3000
A. A neither losses nor gains
B. A makes a profit of 11%
C. A makes a profit of 20%
D. B loses 20%
A. Rs. 3,750
B. Rs. 3,250
C. Rs. 2,750
D. Rs. 2,250
Just substitute the options:
For eg:- if CP = 30 , SP = 39 (Given)
Then gain = SP - CP i.e 39 - 30 = 9
Then, Gain% = 9/30 * 100 = 30% which is same as CP.
-130 and +30 are the roots.... Since we cannot take negative root... 30 is the answer
39*100/130=30 (cp)
39-30=9
9/30*100=30%
simple trick
In this type of questions
Sp ka is tarh fraction kro ki dono k bich 10 ka difference ho
39 = 3*13
Take 0 on both side
30 and 130
ans 130 nhi ho skta because that is more then sp
so our answer is 30.
3900-100x = x2
x2+100x-3900 = 0 and not x2+100-3900 = 0
Derivative, x2+100x-3900 has to be solved to arrive at an answer.
please solve it x^2+100-3900=0
Correct Answer = D