John went to a shop and bought things worth Rs. 75, out of which 90 Paise went on sales tax on taxable purchases. If the tax rate was 18%, then what was the cost of the tax free items?

=> Total tax incurred = 90 Paise
= Rs.90/100
Let the cost of the tax free items = x
Given that tax rate = 18%
∴ (75− 90/100 − x)18/100 = 90/100
⇒ 18(75 −0.9 −x) = 90
⇒ (75 − 0.9 − x) = 5
x = 75 − 0.9 – 5
X=69.1