I did this last year the answer is 9.5
B, is the correct answer.
7% of 450 is 31.5
We add 31.5 to 450 to find out highest possible error, and subtract 31.5 from 450 to find out lowest possible error.
Y X
80 32
100 x'
80x' = 100*32
80x' = 3200
x' = 3200/80
x' = 320/8
x' = 40
Step-by-step explanation:
Consider the provided information.
For the condition statement
or equivalent "If p then q"
The rule for Contrapositive is: Negative both statements and interchange them. 
Part (A) If you are taller than 6 ft, then it is unpleasant for you to travel in economy class.
Here p is "you are taller than 6 ft, and q is "it is unpleasant for you to travel in economy class".
It is given that Your contrapositive must not contain explicit references to negation. Assume that the negation of "unpleasant" is "pleasant".
Contrapositive: If it is pleasant for you to travel in economy class then you are not taller than 6 ft then.
Part (B) "If x ≥ 0 and y ≥ 0 then xy ≥ 0" where x, y are real numbers.
Here p is "xy≥ 0, and q is "x ≥ 0 and y ≥ 0"
The negative of xy≥ 0 is xy<0, x ≥ 0 is x<0 and y ≥ 0 is y<0.
Remember negative means opposite.
Contrapositive: If xy < 0 then x<0 and y<0.
The answer is 0o45.......