math

With the first on I would just graph it.

Put the time on the horizongal (bottom) axis and temperature on the vertical axis.

Then you can just read the answer of the graph.

Hi Critical, 

In future could you please put only one question per post.

second question -

82+88+91+83 = 344

(344+F)/6   will give the score out of 100  (percentage)  

So if he scores a B in what range will F have to lie?

\(80\le \frac{344+F}{6}\le 89\)

Anyway, since only on is an outlier it must be the highest or the lowest one!

So if you totally guess you would have 50% chance of getting it right  :)

Also this means that you only need to check one end, it is either the one that you want or else it must be the one at the other end :)

Solution:

\(\text {Hugo can receive a maximum of 600 points for all tests. }\\ \text {The lowest “B” score is } (0.80 * 600) = 480 \text { points. }\\ \text {The highest “B” score is } (0.899 * 600) =539 \text { points. }\\ \text {Total points for the first four tests are } (82) + (88) + (91) + (83) = 344 \\ \text {For a “B” grade, the final score (F) must have a range of }\\ (479-344) \ge (F) \lt (540-344)\\ \hspace{2.6em} (135) \ge (F) \lt (196)\\ \; \\ \text {Answer “K” exceeds this range. }\\ \)

GA