If Catherine buys 4 burgers and 2 packets of large fries, she will have 30 cents leftover. If she buys 2 burgers and 3 packets of large fries, she will have $2.40 leftover. Given that each burger costs $2.80.

a) Find the cost of one packet of large fries.

b) Find the amount of money that Catherine has.

Source: Assessment