How many dollars does it cost to ship from Node $2$ to Node $4?$

$4.$ How units are ready to be shipped from Node $1?$

$5.$ An inspection of the network flow problem indicates that "demand" and "supply" are equal. $($True or False?$)$

$6.$ An inspection of the network flow problem indicates that there are two paths $($i$.$e$.,$ possible ways$)$ to ship to Node $4.($True or False?$)$

$7.$ What is the demand at Node $4?$