A person pays 10 percent tax on income up to 4.0 lakh, 20 percent on the amount between 4.0 lakh and 8.0 lakh, and 30 percent on the amount above 8.0 lakh. If the total tax paid is 1.8 lakh, find his average percentage of tax paid on the whole income.

The average tax rate is 18%.

Tax on first 4 lakh = 10% x 4 = 0.4 lakh; on next 4 lakh = 20% x 4 = 0.8 lakh.

These cover 1.2 lakh of the 1.8 lakh total tax.

Remaining 0.6 lakh at 30% comes from income 0.6/0.3 = 2 lakh above 8 lakh.

Total income = 8 + 2 = 10 lakh.

Average rate = 1.8/10 x 100 = 18%.