$1.($a$).$ Use the above to calculate the arc price elasticity of demand between PX $=$ $$400$ and PX $=$ $$350.$ The arc elasticity formula is:

E$\_$p $=\backslash$Delta Q$/\backslash$Delta P$($P$\_1+$P$\_2)/($Q$\_1+$Q$\_2)$

$-5000/50$

$($b$).$ Judging from the computation in $1($a$),$ do you expect revenue resulting from the price decrease to $$350$ to increase, remain the same, or decrease relative to the revenue at the price of $$400?($Hint: see the table on page $65$ of Truett$).$ Explain your choice.