Question

imple 16. The marked price of an article is * 2400. A shopkeeper allows two successive discounts
of 15% and 10%. Find the price which a customer has to pay for the article.
The selling price of the article
lution.
1
15
100
10
1
of M.P.
100
85
90
of 2400
85 x 9
10
of 24 = 1836
100
100
EXERCISE 7(B)
26
1. The selling price of a chair is
25
times its cost price. Find the loss or the profit per cent.
7
2. The cost price of an article is
times its selling price. Find the loss or the profit per cent.
4
A trader sells an item at 15% gain. Had he sold it for * 18 more, he would have gained
18%. Find the cost price of the article.
4. If the cost price of 10 items is equal to the selling price of 9 items. Find the profit per cent.
5. If the selling price of 15 articles is equal to the cost price of 12 articles. Find the gain or
the loss per cent.
6. If the cost price of 10 articles is equal to the selling price of 8 articles. Find the gain or the
loss per cent.​

Answer 1

Given :-

• Shopkeeper sold item at 15% gain .

• If he sold it for Rs 18 extra then the profit percentage would be 18% .

To find :-

• The Cost price of product .

Solution :-

Let's assume that the cost price of product is Rs x .

Shopkeeper gained 15% profit over x rupees. So the selling price will be

The formula for selling price when CP is x and profit is 15% is

$\sf{\implies \: \frac{100 + gain}{100} \times cost \: price}$

Using this formula we'll find selling price.

$\implies \: \frac{100 + 15}{100} x$

$\sf{\implies \frac{115}{100} x}$

$\underline{\sf{\implies 1.15x }}$

Now if he sold it at Rs 18 more then the selling price obviously will be 18 Rs more .

→ 1.15 x + 18

Now according to the formula the selling price will be .

$\implies \: \frac{100 + 18}{100} x$

$\implies \: \frac{118}{100} x$

$\underline{\sf{\implies 1.18x }}$

→ 1.15x + 18 = 1.18x

→ 18 = 1.18x + 1.15x

→ 18 = 0.03x

$\implies \: \frac{18}{0.03} = x$

$\underline{\sf{\implies x = \: Rs \: 600 }}$

So we got the cost price of product ie Rs 600.

Verification :-

Selling price when profit was 15%

→ 1.15x = 1.15 × 600 → Rs 690.

Selling price when profit was 18%

→ 1.18x = 1.18 × 600 → Rs 708 .

Now difference between these two

→ 708 - 690 = Rs 18 .

Hence verified.