Forty tiles of dimensions 1 foot × 2 foot each are required to completely cover a floor. How many tiles of dimensions 2 foot × 4 foot each would be required to completely cover the same floor?

A 10

B 20

C 80

D 160

Correct Answer: Option A

smaller tiles = 2*1 = 2 sq ft

40 smaller tiles cover = 40*2 = 80 sq ft area

now,

area of bigger tiles = 2*4 = 8 sq ft

tiles required to cover the same floor = 80/8 = 10 tiles