Question 141351
Let's simplify this problem:
Available:
first: 120
second: 140

Student earns 81% of 120. How many points are needed of 140 to have 80% of 260?

80% of 260: .8*260=208. This means the student needs to end at 208 points. She has .81*120=97.2 points already. This means she needs 208-97.2=110.8 points of the 140 available in the second half of the course. Percentage-wise this is a 79.14%.