Please keep in mind that the ‘Own Figure Rule’ (OFR) is your friend.
Let me give two examples.
1) If you are trying to compute the WACC and you need to find a new equity beta. If you can’t complete that due to time. Simply, assume a number for the equity beta. Tell the marker it is an assumed number. Then use that in CAPM to find Ke & again to find WACC.
You will get FULL MARKS for the Ke & WACC under OFR.
2) If you are asked to comment on your calculations like an NPV. Even if your number is wrong, as long as your comments are correct based on your number, you get full marks under OFR.