Due to a 20% fall in the price of potato, one can buy 3kg of potato more by investing ₹240. What is the original price of potato per kg?

Question

Question

This question was previously asked in

SSC GD Constable Memory Based Test (12 Jan 2023 Shift 1)

Answer 1

Given:

The price of potato fall by 20%, this can buy 3kg potato more by ₹240.

Concept used:

Price is inversely proportional to its consumption.

Calculation:

Let's assume the original price of potato is x /kg

After 20% fall the price becomes \(x × \frac{80}{100} = \frac{4x}{5}\)

The fall of price helps to buy 3kg more ₹240, so,

⇒ \(\frac{240}{\frac{4x}{5}} - \frac{240}{x} =3\)

⇒ \(\frac{240× 5}{4x} - \frac{240}{x} =3\)

⇒ \(x = \frac{60}{3} = 20\)

∴ The original price of potato is ₹20 /kg.

Shortcut Trick

We know, 20% → \(\frac{1}{5}\)

Difference between consumption (5 - 4) = 1 unit

⇒ 1 unit → 3 kg

⇒ 4 unit → (3 × 4) = 12 kg

Now, the original price of potato is \(\frac{240}{12} =\) ₹20 /kg