A man spends 75% of his income.  His income increased by 20% and his expenditure also increases by 10%.  The percentage increase in his savings is:

50%

75% = \(\frac{3}{4}\)

400 (Income)  →  300 (Exp.)    100 (Savings)

  ↓                         ↓

20%                    10%

  ↓                         ↓

480                     330

= 480 - 330 = 150 (new savings)

Change in savings = 50% increased