8x+16y = 39 and 40x+8y = 42 are the system of equations that represents in inches the relationship between the length of a blue tile and the length of a white tile.
Explanation:
Let 'x' be the inches of a blue tile.
Let 'y' be the inches of a white tile.
8x+16y = 39 -------(1)
40x+8y = 42 -------(2)
Multiply eqn(2) by 2 and subtract it from eqn(1)
8x+16y = 39
(-) 80x+16y = 84
-72x = -45
⇒ x = -45/-72
⇒ x = 5/8
∴ Blue tile is 5/8 inches.
substitute x=5/8 in eqn(1)
⇒ 8(5/8) + 16y = 39
⇒ 16y = 39-5
⇒ y =34/16
⇒ y = 17/8
∴ White tile is 17/8 inches.