Question

if 3 litres of petrol costs 195 then find the cost of 8 litres of petrol

Answer 1

By unitary,
1 liter cost=195/3=Rs 65
8 liter cost=8*65=Rs 520

Answer 2

cost of 3 litre petrol=$195
cost of 1 litre petrol=195/3=$65
cost of 8 litre petrol=$[65*8]
=$520