Answer
uncompressed size = 23040000
compression ratio = 9.6:1
Work Step by Step
image size = number of pixels $\times$ pixel size
=> image size = (1200 $\times$ 800) $\times$ 24
=> image size = 23040000
---compression ratio = $\frac{uncompressed size}{compressed size}$
=> compression ratio =$\frac{23040000}{2400000}$
=> compression ratio = 8:5 = 9.6:1
