Alice backyard has 6.25 by 6.25m patio she would like to build a 1.5 M wide extension around three sides of the patio as the figure shows you will by 0.25 by 0.25 M tiles that come 25 tour package how many packages does Ellis need to buy in The extension

To find the area of the extension, I'm going to find the total area (patio and extension) and subtract the patio.

Total area:  length  =  1.5 + 6.25 + 1.5  =  9.25     height  =  1.5 + 6.25  =  7.75

   Total Area  =  9.25 x 7.75  =  71.6875

Area of the patio  =  6.25 x 6.25  =  39.0625

Area of the extension  =  Total Area - Area of the patio  =  71.6875 - 39.0625  =  32.625

Area covered by one box of tiles:  25 x 0.25 x 0.25  =  1.5625

Number of boxes needed:  32.625 / 1.5625  =  20.88  =  21 boxes

Step-by-step explanation:

a_n = a_1 + (n - 1)d

the first term is 6.

the common difference d = ?

when you find d, replace n with 7 and d with the common difference to find your answer.