High school text books don't last forever. The lifespan of all high school statistics textbooks is approximately normally distributed with a mean of 9 years and a standard deviation of 2.5 years. What percentage of the
books last more than 10 years?
34.5%
84.5%
O O O O O
65.5%
11.5%
69%

24

step-by-step explanation:

the graph shows 30% of students walk. 80 students were questioned, so the number that said they walk is

30% × 80 = 0.30 × 80 = 24

answer: im sorry i dont get it

step-by-step explanation:

the height of the surface increases from the center out to the sides of the road.

step-by-step explanation:

as we move out we move away from the x-axis.

and as mentioned in the problem statement that height of a road increases when we move away from the center x.

hence proved that 3rd option

the height of the surface increases from the center out to the sides of the road.

is the correct option.

actually what is a question i don't understand