Answer (B) 2/3
Explanation: the multiplicative rate is the ratio of the values y(k)/y(k+1) (with k being the index). This ratio must be the same for the function to be exponential. We can take y(2)/y(1) = 4/6 = 2/3.
We can use 2/3 to verify the remaining entries:
x=3: 4*2/3 = 8/3 = y(3)
x=4: (8/3)*(2/3)=16/9=y(3)
Not necessarily.

and

may be linearly dependent, so that their span forms a subspace of

that does not contain every vector in

.
For example, we could have

and

. Any vector

of the form

, where

, is impossible to obtain as a linear combination of these

and

, since

unless

and

.
So I believe you will have to do 10% x 7 as it has been seven years which will be 70% and 70% of 8000 is 5600 so the answer will be £5600