A retail bank's sources of funds include savings, time, and checking (current) deposits. In June 2011, Hang Seng Bank, a leading Hong Kong bank, quoted interest rates of 0.01% on savings accounts, 0.15% on a 12-month time deposit, and nothing on checking accounts.

• Suppose that the bank incurs an additional 0.2% cost to administer checking accounts, and 0.1% cost for savings accounts and time deposits. List the three sources of funds in ascending order of annual cost per dollar of funds.
• Suppose that the bank has $2 billion of savings deposits, $5 billion of time deposits, and $3 billion of checking deposits. On a diagram with amount of funds in billions of dollars (from 0 to 10 billion) as the horizontal axis and cost in millions of dollars as the vertical axis, illustrate the (i) average variable cost of funds, and (ii) marginal cost of funds.

I do not understand the second part to this question. I do not understand how the $2 billion, $5 billion and $3 billion factor into the diagram when the x-axis is already labeled from 0-10. Do you multiply the cost by that amount?

For instance:

is the Savings column .11 or .22? if it is .22 is that because it is based on $2 billion or $1 billion?