Most of the information's required for solving this problem is already given in the question. Let us write them down first and then concentrate on the problem in hand.
When y = 5, then x = 2.5
So
y = kx
5 =2.5k
k = 2
Now, when x = 10, then
y = kx
= 2 * 10
= 20
From the above deduction, we can conclude that the correct option among all the options that are given in the question is the last option.
