Answer:
D = 280
Step-by-step 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
