Advertisements
Advertisements
Question
By selling an article for Rs. 21, a trader loses as much per cent as the cost price of the article. Find the cost price.
Advertisements
Solution
S.P. of an article = Rs. 21
Let cost price = Rs. x
Then loss = x%
∴ S.P. = `("C.P." (100 - "loss"%))/(100)`
21 = `(x(100 - x))/(100)`
2100 = 100x - x2
⇒ x2 – 100x + 2100 = 0
⇒ x2 – 30x – 70x + 2100 = 0
⇒ x(x – 30) – 70(x – 30) = 0
⇒ (x – 30)(x – 70) = 0
EIther x – 30 = 0,
then x = 30
or
x - 70 = 0,
then x = 70
∴ Cost price = Rs. 30 or Rs. 70.
APPEARS IN
RELATED QUESTIONS
Solve the following quadratic equations by factorization:
a(x2 + 1) - x(a2 + 1) = 0
Solve the following quadratic equations by factorization:
`5/(x - 2) - 3/(x + 6) = 4/x`
`x^2+8x-2=0`
The difference of two natural numbers is 5 and the difference of heir reciprocals is `5/14`Find the numbers
Solve the following quadratic equations by factorization: \[\frac{2}{x + 1} + \frac{3}{2(x - 2)} = \frac{23}{5x}; x \neq 0, - 1, 2\]
If 2 is a root of the quadratic equation \[3 x^2 + px - 8 = 0\] and the quadratic equation \[4 x^2 - 2px + k = 0\] has equal roots, find the value of k.
The values of k for which the quadratic equation \[16 x^2 + 4kx + 9 = 0\] has real and equal roots are
Solve equation using factorisation method:
2x2 – 9x + 10 = 0, when:
- x ∈ N
- x ∈ Q
Solve the following quadratic equation by factorization method : `"x"^2 - 5"x" - 36 = 0`
Two years ago, a man’s age was three times the square of his daughter’s age. Three years hence, his age will be four times his daughter’s age. Find their present ages.
