Verified Answer :

Ckaranja

D\(\alpha\)t
D=kt
108=k(4)
108=4k
k=\(\frac{108}{4}\)
k=27
The equation connecting D and t is;
D=27t
When t=7,
D=27*7
D= 189

Answer:

189

Step-by-step explanation:

Given : D varies directly with t and D is 108 when t is 4

To Find:  Find D when t is 7

Solution:

D varies directly with t

D ∝ t

So, \(D=kt\)

where k is the constant of proportionality

Now we are given that D is 108 when t is 4

So, \(108=k(4)\)

\(\frac{108}{4}=k\)

\(27=k\)

Thus the constant of proportionality i.e. k = 27

So, \(D=27t\)

Now substitute t = 7

So,  \(D=27(7)\)

\(D=189\)

So, D = 189 when t = 7

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