Question

Chalk contains calcium,carbon and oxygen in ratio 10:3:12. Find the percentage of carbon in chalk. In a chalk stick the weight of carbon is 3g. What is the weight of chalk stick?

and

Juhi sells a washing machine for Rs. 13,500. She loses 20% in the bargain. What was the price at which she bought it?​​

Answer 1

Answer (1) :

(I) Given Ratio = 10 : 3 : 12

Total part = 10 + 3 + 12 = 25

$\sf \: Part \: of \: Carbon = \dfrac{3}{25}$

Percentage of Carbon part in chalk =

$= \: \dfrac{3}{25} \times 100 = 12\%$

(ii) Quantity of Carbon in Chalk stick = 3g

Let the weight of Chalk be x grams.

Then 12% of x = 3.

Answer (2) :

Selling Price of Washing machine = Rs. 13,500

Loss Percentage = Rs. 20%

Let the cost price of washing machine be x.

Since, Loss = Loss% of C.P

$\implies \sf \: loss \: = 20\% \: of \: rs.x \: = \dfrac{20}{100} \times (x) \: \dfrac{x}{5}$

Therefore, S.P = C.P - Loss

$\implies \sf \: 13500 \: \: x - \dfrac{x}{5}$

$\implies 13500 = \sf\dfrac{4x}{5}$

$\implies \sf \: x \: = \dfrac{13500 \times 5}{4} = Rs. 16857$

Hence, 16,875 is the price she bought.

Know more :-

$\sf \red{S.P } = \blue {C.P - Loss}$