Is CHS the same as Moon high school? I have assumed it is, so moon has a budget of 60k, and is planning on spending 20k on computers.C.H.S. currently plans to spend $20,000 on computers.
A budget constraint represents the trade off between expenditure on computers (C) and all other goods (X). So if they dont spend anything on C, they will spend $60000 on X, and if they only consume C, they wont spend anything on X. So the budget constraint is the linear line between these two maximum expenditures.
Under Plan (a) They receive a lumpsum grant in which they can spend how they wish on the 2 goods. So it will shift the budget constraing (BC) out by $10,000.
Plan (b) [Edit: Im not exactly 100% sure with part (b)] they receive the $10000 payment, however they must increase their expenditure on computers by $10000 first. I am assuming that once they have increased their expenditure, they are then free to use the grant money how they want. This causes the budget constraint to 'jump up' at their current level of expenditure on computers.
Under plan (c) they will recieve 50c for each dollar spent on computers. So if they spend all 60k on computers, they will receive a 30000 grant, however if they spend $60000 on X they wont receive any grant at all. At $20,000 the grant would be $10000.
Plan (d) is similiar to (c) only they cap the grant at $10000 instead of letting it be unlimited.
Just drawing up some graphs in MS paint now to help explain what I mean