Tata Docomo charged Rs. 540 for 1GB(1 day)and Aircel charged 90% of Rs. 540 for the same 1GB for the same days. Gowri uses Docomo for 1st 15 days and the remaining 15 days uses Aircel. If she uses Aircel for the whole 30 days, how much amount she save?

Step 1: Calculate the cost of using Tata Docomo for 15 days. Tata Docomo charges Rs. 540 for 1GB per day. So, for 15 days, the cost would be 540 * 15 = Rs. 8100.

Step 2: Calculate the cost of using Aircel for 15 days. Aircel charges 90% of Rs. 540 for 1GB per day. So, the cost per day would be 90/100 * 540 = Rs. 486. For 15 days, the cost would be 486 * 15 = Rs. 7290.

Step 3: Calculate the total cost of using both services for 30 days. The total cost would be the cost of using Tata Docomo for 15 days plus the cost of using Aircel for 15 days. So, the total cost would be 8100 + 7290 = Rs. 15390.

Step 4: Calculate the cost of using Aircel for the whole 30 days. The cost of using Aircel for 1 day is Rs. 486. So, for 30 days, the cost would be 486 * 30 = Rs. 14580.

Step 5: Calculate the amount saved by using Aircel for the whole 30 days. The amount saved would be the total cost of using both services for 30 days minus the cost of using Aircel for the whole 30 days. So, the amount saved would be 15390 - 14580 = Rs. 810.

Therefore, Gowri would save Rs. 810 by using Aircel for the whole 30 days.