A toy is sold for Rs. 220, what was the cost if the rate of profit was 10% of the cost?

A) Rs.196

B) Rs.198

C) Rs.200

D) Rs.210

Given Data 

S.P = 220     Gain=10%  C.P=?

We know that :

S.P=[ 100 +Gain]/100 * C.P 

We Have to find C.P, so re-arrange formula 

⇒ C.P= 100/[ 100 +Gain] * S.P

Putting given data:

⇒ C.P= 100/[ 100 +10] * 220

⇒ C.P=200