Part b : which phrase from the poem provides the best clue to the meaning of "constrained"?

I'd have to see the poem to actually help you, but without any context the word 'constrained' usually means forced or overly controlled.

the amount of the purse is, $120.

tax rate =9%

first find the the total tax she paid on the amount is equal to the 9% of $120 i.e,

now,

total amount paid by shalika = $120 +$10.8 = $130.8