a. Cross price elasticity = 0.75

b. The total amount Jill had= $9000

Explanation:

a) Cross price elasticity = (%change in quantity of Good B)/(%change in price of good A)

%change in quantity of Good B = 30%

%change in price of good A = (10-6)/10 * 100%

=40%

Cross price elasticity = 30/40 = 0.75

b) The amount Spend of $5000 is before the period and therefore not subject to 10% interest.

The amount subject to 10% interest is the $4400.

If the amount earned a 10% interest, then it is equivalent to 110%.

We therefore compute 100% which is the initial amount.

Initial amount = 100/110*$4400 = $4000

The total amount Jill had is $5000+$4000 = $9000