91Ó°ÊÓ

Increase percentage is given by

$\text{increase percentage=}\frac{\text{increase}}{\text{original number}}×100$

where increase = new number – original number

Initially Matt had 30 CDs.

Since he gave away 2 CDs, the number of CDs left now is 30-2=28

After this he purchased 6 new CDs. Therefore, the number of CDs he has now is 28+6=34

He then traded 3 of his CDs to Kashan for 4 of Kashan’s CDs. Hence the number of CDs he has is 34-3+4=35

Therefore, the total number of CDs Matt have since 2000 is 35.

Using original number as 30 and new number as 35 in increase percentage formula, the following is obtained:

$\begin{array}{c}increase\%=\frac{35−30}{30}×100\\ =\frac{5}{30}×100\\ =\frac{50}{3}\\ =16\frac{2}{3}\end{array}$

Hence the percentage of increase in the number of CDs in Matt’s collection is $16\frac{2}{3}\%$

Therefore, option D is correct.