Geeta saved Rs. 300 and Meeta saved Rs. 450. They each spend half of their money on a trip to the mall, so Geeta spends Rs. 300/2 = Rs. 150 and Meeta spends Rs. 450/2 = Rs. 225.

After spending money on the trip, Geeta will have Rs. 300 – Rs. 150 = Rs. 150 left. After spending money on the trip, Meeta will have Rs. 450 – Rs. 225 = Rs. 225 left.

When they join their money, the total amount they will have is Rs. 150 + Rs. 225 = Rs. 375.

To buy a Barbie doll that costs Rs. 660, they need Rs. 660 – Rs. 375 = Rs. 285 more.