If i had a 65% in a course now, and i need a 70% to pass, What will i need to get on my final exam worth 25% to pass the course?

Let the mark needed by x

then .65(70) + .25x = 70
x= 98

Good luck!

check:
70(.65) + .25(98) = 45.5 + 24.5 = 70