The materials used by Hibiscus Company's Division A are currently purchased from an outside supplier at $$52$ per unit. Division $B$ is able to supply Division A with $15,900$ units at a variable cost of $$47$ per unit. The two divisions have recently negotiated a transfer price of $$48$ per unit for the $15,900$ units. Enter an increase as a positive number and a decrease as a negative number.

a$.$ By how much will each division's income increase as a result of this transfer?

Division $A$ $

Division B $

b$.$ What is the total increase in income for Hibiscus Company?

$