I have a 70% in my class and I am trying to finish with a 75%. I have my summative worth 15% and I got a 80% what’s my mark now ?

To calculate your overall mark, we need to consider the weight of each component. Since your summative is worth 15% of your total grade, we can calculate its contribution to your mark as follows:

Contribution from summative = summative grade * summative weight
= 80% * 15%
= 0.8 * 0.15
= 0.12

Now, let's calculate how much your current mark improved after the summative:

Current mark improvement = (75% - 70%) * (100% - 15%)
= 5% * 85%
= 0.05 * 0.85
= 0.0425

Now, we can add the contributions from the summative and the improvement to your original mark:

New mark = current mark + contribution from summative + current mark improvement
= 70% + 0.12 + 0.0425
= 0.70 + 0.12 + 0.0425
= 0.8625

Therefore, your new mark after the 80% on your summative is approximately 86.25%.