Option 4 : Rs. 132

__Shortcut Trick__

Formula used:

Successive increase % = {x + y + (xy/100)}%

Where,

x = first increase %

y = second increase %

Calculation:

Here, x = 20%

y = 10%

According to the formula, we have

Overall increase % = [20 + 10 + {(20 × 10)/100}]%

⇒ (30 + 2)%

⇒ 32%

New price = Rs. (100 + 32% of 100)

⇒ Rs. {100 + (32/100) × 100}

⇒ Rs. (100 + 32)

⇒ Rs. 132

∴ The cost of article at the end of second month is Rs. 132.

The basic method is given below.

**Given:**

Cost of article = Rs. 100

Price increase by 20% and 10% for the first and the second month respectively

**Calculation:**

After first month, price of article = Rs. {100 + (20% of 100)}

⇒ Rs. {100 + (20/100) × 100}

⇒ Rs. (100 + 20)

⇒ Rs. 120

Now, for the second-month price is increased by 10%

So, price of the article at the end of second month = Rs. {120 + (10% of 120)}

⇒ Rs. {120 + (10/100) × 120}

⇒ Rs. (120 + 12)

⇒ Rs. 132

**∴ The cost of article at the end of second month is Rs. 132.**