Question

**** Price of a commodity is first increased by x% and
then decreased by x%. If the new price is K/100,
find the original price.

(a) (x - 100)100/K
(b) (x2 - 1002)100/K
(c) (100 - x)100/K
(d) 100K/(1002 - x?)​

Answer 1

Answer:

(d)

Step-by-step explanation:

Let the original price be a.

When it is increased by x%:

= > a + x% of a

= > a(1 + x%)

When decreases by x%:

= > a(1 + x%) - x% of a(1 + x%)

= > a(1 + x%){ 1 - x% }

= > a{1² - (x%)²} {(a+b)(a-b)=a²-b²}

In question, new price is k/100:

= > a(1² - (x²/100)²) = k/100

= > a(100² - x²)/100² = k/100

= > a(100² - x²) = 100²k/100 = 100k

= > a = 100k/(100² - x²)

Original price was 100k/(100² - x²)