Question

The Pet Palace is replacing its dog training arena with a new arena with dimensions that

Answer 1

(A) 450 ft squared.

First, calculate the old arena's dimensions. 
10 x 15 = 150.

Calculate the new arena's dimensions.
20 x 30 = 600.

Now subtract 150 from 600.
600 - 150 = 450. 

Hope I helped!