Brainliest reward if you get this right plus 20 points

The equation of the relation ⇒

y = 18

Step-by-step explanation:

∵ y ∝ x/z

∴ y = kx/z

∵ y = 18 , x = 15 and z = 5

∴ 18 = 15k/5 ⇒ 18 = 3k

∴ k = 18/3 = 6

∴ y = 6x/z

∵ x = 21 and z = 7

∴ y = (6 × 21)/7 = 18

it is true

step-by-step explanation:

all the combinations add up i used   calculator

answer: 7 x 2/5 = 2.8 hours, is your answer. your welcome! : 3

step-by-step explanation: first work out how long it took to hose 1/7 of the lawn which is 2/5 hours. times that by 7 to get the whole lawn.

sorry i don't know the other answer. i didn't learn what a proportional relationship is.