Well first off the question doesn't make sense... did you re-word it from perhaps: how many subnets and hosts per subnet from 172.26.0.0 when using a subnet of /26?
but in any case, the class b default subnet is 255.255.0.0 and you are breaking that into 255.255.255.192. So you have 16 bits by default for that classful network and you are adding an additional 10 network bits (subtracting 10 from the host bits). you use the math of 2^n where n equals the network bits you are "Stealing" from the host bits and get:
Then the hosts is (2^h)-2 so we have 6 host bits left over and we get: 2^6=64-2=62
Hope this helps =)
Ryan -- Human beings, who are almost unique in having the ability to learn from the experience of others, are also remarkable for their apparent disinclination to do so. -Douglas Adams
The question looks like it came from subnettingquestions.com. It assumes you have control of the entire 172.26.0.0 subnet and you have decided to subnet it down to a /26. Look at it the other way. What do I need to do to 172.26.0.0/16 to turn it from a single network in to 1024 subnets with 62 hosts per subnet? Answer, I need to give it a /26 mask and get counting!