QUESTION $3$

An Internet Service Provider $($ISP$)$ is granted a block of addresses starting with $150\mathrm{.}80\mathrm{.}0\mathrm{.}0/16.$ The ISP wants to distribute the block to $2600$ customers as follows.

The first group $200$ medium$-$size businesses, each needs $128$ addresses.

The second group has $400$ small businesses, each need $16$ addresses.

The third group has $2000$ households, each need $4$ addresses.

Design the sub$-$blocks and give the slash notation for each sub$-$block. Find out how many addresses are still available after these allocations.