Question

Man spends 75% of his income. His income increased by 20%. His expenditure also increased 10%. Find increase in his expenditure.

Answer 1

Suppose the man's income is 100 units.
His expenditure is 75 units.

His new income = 100 units + 20/100 * 100 = 120 units.

His new expenditure is   (75+10)% = 85%  of 120 units 
            = 102 units

Increase in expenditure  =  102 - 75 = 27 units 
                   = 27/75 * 100  = 36%