How long would it take to transfer a 600-MB database from disk to memory over a DMA channel with a bandwidth of 2.5 GB/s?

0.24 seg

Explanation:

We have 600 MB of data if we convert it to Gb we get 0.6Gb of data, the bandwidth is telling us that we can transfer 2.5 Gb of data per second if we assume that the data transfer is lineal we can apply the rule of three to solve the problem:

2.5 Gb - > 1 seg

0.6 Gb - > X

Applying the cross multiplication we get that X = 0.6 Gb * 1 seg / 2.5 Gb = 0.24 seg