The number of tiles Mary will need are 36 tiles
The steps used to find the number of tiles Mary will need can be presented as follows;
The dimensions of the possible picture frame in the question are;
Inner frame size; 4 in × 7 in
The width of the frame = 1 tile wide
The dimensions of a tile = 1 inch square
Therefore; Outer frame size; (4 + 2 × 1) in × (7 + 2 × 1) in = 6 in × 9 in
The number of tiles Mary will need, can be obtained from the area of the outer frame and the area of 1 tile
Area of the outer frame is; 6 in × 9 in = 36 in²
Number of tile = Area of outer frame/(Area of 1 tile)
Number of tiles she will need is; 36 in²/1 in²= 36 tiles
The possible question, obtained from a similar question found through search can be presented as follows;
Tina is going to put 1-inch square tiles on the picture frame shown below
a. If the frame is one tile wide, how many 1-inch-square tiles will she need
Please find attached the drawing of the picture frame, created with MS Word