Question

if 5 litres of oil cost rupees 37 point 50 how much will 9 litres of all cost

Answer 1

cost of 1 litre of oil=37.50/5
=7.50
cost of 9 litres of oil=9×37.50

Answer 2

cost of 5 litre oil=37.5
by unitary method
cost of 9litre oil =
$\frac{37.5}{5} \times 9 = 67.5$