Answer:
4/5
Step-by-step explanation:
I don't know what you mean by benchmark but this is adding fractions. when you add fractions you must have the same denominator. 10 and 5 are not the same so you need to find the same denominators conveniently 2/5 is equivalent to 4/10 (by multiplying the fraction by 2) then you add the numerator straight across keeping the same denominator. that would be 5/10. Simplify to the is 1/2
It would take 328 seconds or 5 minutes and 47 seconds
Try drawing your graph, and labeling it 50-60 going up. Then plot the numbers as close as you can! :)