In a previous comment Jon P. already gave a comprehensive answer with a great deal of explanation, so I am just adding couple thoughts in this regards.

By virtue of having the tag "Fractions" associated with this question and making some "qualified guess" it seems that the expected answer would pertain more to fractions arithmetic rather than test "weighting algorithms", so Method 2 would probably take precedence. Furthermore, based on this assumption, the fraction calculations can be performed simply as:

** (26/30 + 24/30 + 70/100) = 2 11/30** (or **2.366667** as a decimal rounded to 6 digits)

and then multiplied by improper fraction **100/6** to get the marks out of 50, resulting in:

**2 11/30 x 100/6 = 39 4/9** (exact fraction) or **39.444444** written as a decimal rounded to 6 digits.

Some logical explanation beyond the computation method. Adding all 3 fraction and dividing the result by 3 essentially will give the *average* value of the non-weighted test scores, namely: 71/90, or 0.788889 as a decimal number, or the mark 78.889 out of 100. Consequently, dividing the latter by half will result in the mark 39.44 (rounded).

Please notice the small rounding error in the original Method 2 calculations due to intermediate fractions-to-decimal conversion. The exact value is provided in my computation method, namely: **39 4/9**. In order to simplify the computation I’ve been using the online 3-Fractions calculator, which provides both fraction/decimal results (http://webinfocentral.com/math/fractions.aspx).

Hope this may help. Best regards,

Arthur D.

09/11/15