Question

S varies directly as t. if s is 20 when t is 4 then t is ____ when s is 30

Answer 1

Thus, t = 6 if s = 30.

Explanation:

Given that,

→ The value of s is 20 when t is 4.

Now value of s when t is 1,

→ s = (20/4)t

→ [ s = 5t ]

Then value of t when s is 30,

→ 5t = 30s

→ t = (30/5)s

→ t = 30/5

→ [ t = 6 ]

Hence, the value of t is 6.

Answer 2

• t is 6 when s is 30

--------------------------

s varies directly as t:

• s = kt, where k- constant of direct variation.

If s is 20 when t is 4, find the value of k:

• 20 = 4k ⇒ k = 20/4 ⇒ k = 5

The equation is:

• s = 5t

When s is 30, then t is:

• 30 = 5t ⇒ t = 30/5 ⇒ t = 6