Answer:
There are 80 marks in total.
Step-by-step explanation:
Let the number of total marks be [tex]x[/tex].
The percentage score of the student can be written as the ratio
[tex]\displaystyle \frac{68}{x} = 85\%[/tex].
However,
[tex]\displaystyle 85\% = \frac{85}{100}[/tex].
Equating the two:
[tex]\displaystyle \frac{68}{x} = \frac{85}{100}[/tex].
Cross-multiply (that is: multiple both sides by [tex]100x[/tex], the product of the two denominators) to get
[tex]85x = 68\times 100[/tex].
[tex]\displaystyle x = \frac{68\times 100}{85} = 80[/tex].
In other words, there are 80 marks in total.
