What would be the total downstream throughput when two QAM channels with 38 Mbps each are bonded?

When two QAM (Quadrature Amplitude Modulation) channels are bonded, their data rates can be combined to provide greater throughput. In this case, each QAM channel has a throughput of 38 Mbps.

To find the total downstream throughput, you simply add the throughput of both channels together:

38 Mbps + 38 Mbps = 76 Mbps.

This doubling of the throughput is feasible when the channels are effectively bonded, allowing for simultaneous utilization of both channels to increase the data capacity. Thus, the correct total downstream throughput from bonding two QAM channels, each providing 38 Mbps, is indeed 76 Mbps.

The other options do not reflect the correct mathematical addition of the two channels' throughput, which is why they do not represent the correct answer.