Algebra Question! How many cubic inches are in 20 cubic yards?

Question

(A) 46656 in³

(B) 8640 in³

(C) 46656 in²

(D) 933120 in³

(E) None of these

Answer 1

This problem makes use of the Multiplicative Identity (that is, 1). Any number multiplier by 1 remains the same (although units may change).

1 = (1 yard) / (36 inches) = (36 inches) / (1 yard) [choose the one that allows units to cancel]

20 cubic yards

20 * (1 yard) * (1 yard) * (1 yard)

20 * (1 yard)*1 + (1 yard)*1 * (1 yard)*1

20 * (1 yard)*( (36 inches)/(1 yard) ) * (1 yard)*( (36 inches)/(1 yard) ) * (1 yard)*( (36 inches)/(1 yard) )

20 * 36 * 36 * 36 * (1 inch)*(1 inch)*(1 inch)

933120 cubic inches