# Math Help - area probelms

1. ## area probelms

1.How many 4' * 8' sheets of drywall do you need for the walls of a 12' * 20' room, 8ft high?

2.If ceramic tiles are 8'' * 8'', how manyu tiles would it take to cover an area 4' * 6'?

3. if a customer buys 20 2 * 4's 8ft long, at \$4.75 each, how much would the 2 * 4's cost?

2. [quote=raheel101;185090]1.How many 4' * 8' sheets of drywall do you need for the walls of a 12' * 20' room, 8ft high?

See here,

Area of four walls (on which you need dry-walls) $= 2\times (12 + 20) \times 8= 512 \;ft^2$

Area of one sheet of dry-wall $= 4 \times 8 = 32 \;ft^2$

Number of drywalls $= \frac {512}{32}= 16$

3. 2.If ceramic tiles are 8'' * 8'', how manyu tiles would it take to cover an area 4' * 6'?

See here,

Area to be covered $= 4 \times 6 = 24 \;ft^2= 24\times 144 \;in^2 = 3456\;in^2$

Area of one tile $= 8 \times 8= 64 \;in^2$

Number of tiles $= \frac{3456}{64}=54$