Two ways to think of this one. 30% of 48 is .3*48 = 14.4. So, they need to sell 48+15 = 63 TVs, rounding up since they presumably can't sell fractional TVs.
Other way to view it is that a 30% increase means the new total will be 130% of old. Therefore, required sales are 1.3*48 = 62.4. Again, we round up to 63.