A dishonest trader says to customers that he sells his goods at a cost price, but he uses a false weight and gains 12.5% as profit. How many grams does he use to weigh 1 kg?

Question

Question

This question was previously asked in

SSC CGL 2022 Tier-I Official Paper (Held On : 03 Dec 2022 Shift 4)

Answer 1

Given:

A dishonest trader says to customers that he sells his goods at a cost price, but he uses a false weight and gains 12.5% as profit.

Formula used:

Gain % = [(Error)/(True value – Error)] × 100

Calculation:

According to the formula,

12.5 % = [Error/(1000 – Error)] × 100

⇒ 1/8 = [Error/(1000 – Error)]

⇒ 8Error = (1000 – Error)

⇒ 8Error + Error = 1000

⇒ 9Error = 1000

⇒ Error = 1000/9

So, the trader gives 1000 - 1000/9

⇒ [9(1000) - 1000]/9

⇒ (9000 - 1000)/9

⇒ 8000/9

⇒ 888.8 g

∴ He uses 888.8 g to weigh 1 kg.

Shortcut Trick

We know 12.5% = 1/8

So, the trader instead if giving 9 unit gives only 8 unit (12.5% as profit by false wight)

So, 9 unit → 1000g

Then, 8 unit → 1000/9 × 8 = 888.8 g