This is a typical question a student at any Business School have to deal with during the test. Could you please give me insight on how to solve it. What area of study should I invest in?
A student has obtained an average of 47% across the seven subjects that he has taken so far.
When he takes his eighth and final subject what mark must he obtain to ensure that his overall mark is 50%?
I apologize if the question below has the wrong tag.
Initially we have $$\frac{x_1+x_2+\dots+x_7}{7}=0.47$$ Which implies that $$x_1+x_2+\dots+x_7=7\times 0.47=3.29$$ Therefore $$\frac{x_1+x_2+\dots+x_8}{8}=0.50$$ $$\frac{3.29+x_8}{8}=0.50$$ $$3.29+x_8=8\times 0.50$$ $$3.29+x_8=4$$ $$x_8=4-3.29=0.71$$ As far as what you should study to solve this, I'd say the arithmetic mean, algebra and of course percentages.