Squares& rectangles

[Fokin]

How many squares with sides 1/2 inch long are needed toc cover a rectangle that is 4 feet long and 6 feet wide?

(a) 24
(b) 96
(c) 3456
(d) 13824
(e) 14266
Answer - D

I've resolved in the following way:
1) S of 1 square= 1/2*1/2=1/4 inch
2) s of rectangular = 4*6=24 feet
3) 24*12/ 1/4=1152
Please to advice, what does it wrong?

[albatross86]

4 feet = 48 inches and 6 feet = 72 inches

You need 96 rows and 144 columns.

Total squares = 96*144 = 13824

Pick D.

Your mistake is simply that you forgot to multiply by 12 twice for the area. It is square feet = 144 square inches

So it should be 24*12*12/ (1/4) = 13824

Your approach is fine.

[outreach]

1 feet=12 inch
hence 1/2inch=1/24 feet

area of square=1/24*1/24
area of rectangle =24 feet

squares needed to cover rectangle are

area of rectangle/are of square=24*24*24

hence D