Originally Posted by

**running-gag** Hi

The first one

1. A man spends 75% of his income, when his income is increased by 20%, he increases his expenditure by 10%. By how much per cent are his savings increased?

Let I be his income

His expenditure is 0.75I

His saving is I-0.75I = 0.25I

His income is increased by 20% => new income is 1.2I

He increases his expenditure by 10% => New expenditure is 1.1 x 0.75I = 0.825I

New saving is 1.2I - 0.825I = 0.375I

His saving increased by (0.375I - 0.25I)/0.25I = 50%