Answer:
i) y∝x => y = kx and k = 2.5
ii) When x = 7, y is 17.5
Explanation:
If y is directly proportional to x then according to the question
y∝x which means y =kx where k is any constant
From the above example
8y=20x comparing it with y = kx
y = (20/8)x
y = 2.5x
Here k = 2.5
i) y∝x => y =2.5x
ii) if x=7 then y = ?
From above
y=2.5x
Put x = 7
y = 2.5 x 7
y = 17.5