Answer:
192
Explanation:
The 7 part of the ratio relates to Taylor's 84 CDs
Divide the amount by 7 to find the value of one part of the ratio.
84 ÷ 7 = 12 ← value of 1 part of the ratio, then
9 parts = 9 × 12 = 108 ← number of CDs Dave has
Total CDs = 84 + 108 = 192