When working with very large or very small numbers, scientists, mathematicians, and engineers use scientific notation to express these quantities. Scientific notation is a mathematical abbreviation, based on the idea that it is easier to read an exponent than to count many zeros in a number. Very large or very small numbers need less space when written in scientific notation because the position values are expressed as powers of 10. Calculations with long numbers are easier to do when using scientific notation
Answer:
I think it might be 1 17/18
(not sure)
Step-by-step explanation:
what I did was break down 3 1/2 and I got 2 3/2 I then Subtracted that by 1 5/9 (I don't know if it's right sorry if I'm wrong)
Given:
Sides of triangles in the options.
To find:
Which could NOT be the lengths of the sides of a triangle.
Solution:
Condition for triangle:
Sum of two smaller sides of a triangle must be greater than the longest side.
In option A,

Sides 5 in, 5 in, 5 in are the lengths of the sides of a triangle.
In option B,

Sides 10 cm, 15 cm, 20 cm are the lengths of the sides of a triangle.
In option C,

Sides 3 in, 4 in, 5 in are the lengths of the sides of a triangle.
In option D,

Since, the sum of two smaller sides is less than the longest side, therefore the sides 8 ft, 15 ft, 5 ft are not the lengths of the sides of a triangle.
Therefore, the correct option is D.
He arrives at 9:30 because if you take 8:40 (when dealing with time I like to think of it as a whole number so 8:40 would become 840) then just add 50 minutes to 8:40 (or 840+50 which equals 890 also know as 9:30 because you have to subtract 60 from 90 (because 60 is the limit in time (well technically 59 is)) then add one to 8 like so, which equals 9:30 Enjoy!=)