Raffe wrote three math tests each worth 20% of his final grade. Raffe got marks of 68%, 74%, and 84 %. What mark must Raffe get on the final exam (worth 40%) if Raffe wants a final grade of 70%? Step by step explanation break down solve for x step by step
Let x represent the mark Raffe must get on the final exam.
To find the final grade, we must calculate the weighted average of all tests.
Raffe's weighted average:
0.20(68%) + 0.20(74%) + 0.20(84%) + 0.40(x) = 70%
Simplify the equation:
0.2(68) + 0.2(74) + 0.2(84) + 0.4(x) = 70
13.6 + 14.8 + 16.8 + 0.4x = 70
45.2 + 0.4x = 70
0.4x = 24.8
x = 24.8 / 0.4
x = 62
Therefore, Raffe must get a mark of 62% on the final exam to achieve a final grade of 70%.