Correct Answer - Option 1 : 20

**Given:**

Rekha spends 75% of her monthly income.

Her income increases by 15% and still,

She saves the same amount as before.

**Formula Used:**

Income = Expenditure + Savings

**Calculation:**

Let the income of Rekha be Rs. 100

She spends 75% of 100

Rekha's Expenditure = 75/100 × 100

⇒ Rekha's Expenditure = 75 ----(I)

Rekha's savings = 100 – 75

⇒ Rekha's saving = Rs. 25

Now her income increased by 15%,

⇒ 100 + 15% of her income

⇒ 100 + 15/100 × 100

⇒ Rs. 115

Still Rekha's saving is still Rs. 25

Then her expenditure is,

⇒ 115 – 25

⇒ Rs. 90 ----(II)

Her increase in expenditure,

⇒ 90 – 75

⇒ Rs. 15

Percent increase in Expenditure = Increase/Expenditure × 100

⇒ Percent increase in Expenditure = 15/75 × 100

⇒ Percent increase in Expenditure = 20%

**∴ The percent increase in her expenditure is 20%.**