Fatima finds that if she buys 3 kg of cashews she will have ₹60 left, but to buy 5 kg she would need ₹40 more. If the price then falls by ₹20 per kg, how many kilograms can she buy with all her money?

Explanation

1. 01

   Let the price be ₹$p$ per kg. Her money is $3p + 60$ and also $5p - 40$.

2. 02

   $3p + 60 = 5p - 40$, so $2p = 100$ and $p = 50$.

3. 03

   Her money $= 3 \times 50 + 60 = ₹210$.

4. 04

   New price $= 50 - 20 = ₹30$ per kg, so she can buy $210 \div 30 = 7$ kg.