Question

q is directly proportional to r, q has a value of 24 when r = 16. Find the value of q when r is 12.

if u no answr u ar gey

Answer 1

The statement " x varies directly as y ," means that when y increases, x increases by the same factor. In other words, y and x always have the same ratio that is:

x=ky

where k is the constant of variation.

Here, it is given that p varies as q if p=5 and q=10, therefore,

p=kq

⇒5=k×10

⇒5=10k

⇒k=

10

5

=

2

1

Thus, the general equation is p=

2

1

q.

Since p=20, therefore,

p=

2

1

q

⇒20=

2

1

q

⇒q=20×2=40

Hence, q=40 when p=20.