Math equation problem

May 28, 2015 5:31 AM

Asking for a friend: I have a question about how to work out a student's exam mark. Unit 1 is worth 60%, Unit 2 is worth 40%. Both units are marked out of 80. For example, a student scores 67/80 on unit 1 and 69/80 on unit 2. What is their overall mark? Thanks for any help!
posted by charlen to Grab Bag (8 answers total)

Best answer: You just multiply each exam questions by its worth. So (67/80)*.6 + (69/80)*.4.
posted by stripesandplaid at 5:34 AM on May 28, 2015 [2 favorites]

Best answer: I would do ((67*.6) + (69*.4))/80
posted by AugustWest at 5:35 AM on May 28, 2015

Yup! What stripesandplaid said.
posted by math at 5:35 AM on May 28, 2015 [2 favorites]

Best answer: 0.6 * (67/80) + 0.4 * (69/80) = 84.75%
posted by TORunner at 5:35 AM on May 28, 2015 [2 favorites]

And to be clear, AugustWest's solution is also correct and is the same as stripesandplaid.
posted by math at 5:36 AM on May 28, 2015 [2 favorites]

And TORunner. OK, we can stop now.
posted by math at 5:36 AM on May 28, 2015 [2 favorites]

Best answer: And for future reference, the googlable keywords you are looking for are "Weighted average" or "weighted mean."
posted by If only I had a penguin... at 6:14 AM on May 28, 2015 [4 favorites]

If you don't require the answer to be "over 80," you could make it over 400. It's basically the same as what people have suggested. Add (3 times unit 1's score) to (2 times unit 2's score).
posted by halifix at 12:50 PM on May 28, 2015