If d varies directly with t and d is 108 when t is 4, find d when t is 7.

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,

where k is the constant of proportionality

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

So,

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

So,

Now substitute t = 7

So,  

So, D = 189 when t = 7

answer: 177/8

step-by-step explanation: