To determine which laptop downloads the files at a faster rate, the first step is to determine the unit rate for each of them. This means, you have to determine the number of GB per second they download.
To calculate the GB per second, you have to divide the amount of GB downloaded by the time it took:
DeAndre's download
9 GB in 15 seconds
The download rate is 0.6 GB/s
Cheryl's download
32GB in 80 seconds
The download ate is 0.4 GB/s
DeAndre's laptop downloads at a faster rate.