Question

If D varies directly with t and D is 105 when t is 3, what is D when t is 8

Answer 1

D = 280

Explanation:

We are given that

D∝t

Using constant of proportionality k we can say that

D=kt

where k is always constant for all values of t and D

now we are given that for t=3 , we have D=105

This will help us to determine k , once we have the value of k , we can determine the D when t=8

Hence Now we have

D=105 when t=3

putting them into

D=kt

105=3k

k=35

Hence we now know the value of k as 35

Now we find D at t=8

D=kt

D=35 x 8

D=280

Hence this is our answer D= 280