Each packet of SOAP costs Rs. 10. Inside each packet is a gift coupon

Things to remember from prompt -
Each Packet cost = Rs 10.
Ms. X kept buying packet after packet of SOAP till she could get one set of coupons that formed the word SOAP

Need to find how many P's were found.

Statement 1 - The last label obtained by her was S and the total amount spent was Rs. 210.

From this we just know that SOAP was formed as X spent total 210. Hence we have at least 1 SOAP each. But how many more than that, we are not sure.

Hence Insufficient.

Statement 2 - The total number of vowels obtained was 18.

This does not help in getting the count of P in any way. Hence Insufficient.

Combining Statement 1 and Statement 2 -

Total = Rs. 210
Vowels = 18, i.e. Rs. 180 spent on vowels

Remaining = Rs. 30
Out of that Rs. 10 spent on purchased S as per statement 1.

Remaining = Rs.20
Now for 20, we have two cases -
1. Both 'P'
2. One 'P' and other 'S'.

Now X, would have got both 'P' because 'S' was the last obtained. If X would have got One 'P' and other 'S', then the total would have stopped at Rs. 200 only as her ultimate aim was to form only one SOAP, as mentioned in the prompt.

Hence Count of P = 2 and combining Statement's 1 and 2 was sufficient.

Answer = C