Pls help me answer this too <3 A race official needs to know how long it takes an average contestant to run an obstacle course. There are a total of 200 contestants. How can he find a reasonable estimate for the amount of time it takes to run the obstacle course?

time any contestant on the course and use that time

time himself on the course and use that time

time 2 contestants and average their times

time 20 contestants and average their times

a

step-by-step explanation:

a

practice. practice. practice.

x=half

step-by-step explanation:

x = ±sqrt(10)

step-by-step explanation:

5 - 2x² = -15

subtract 5 from each side

5-5 - 2x² = -15-5

-2x^2   = -20

divide by -2 on each side

-2x^2   /-2= -20/-2

x^2 =10

take the square root on each side

sqrt(x^2 )=±sqrt(10)

x = ±sqrt(10)

check:

5 - 2x² = -15

+sqrt(10)

5 - 2(sqrt(10))² = -15

5 -2(10) = -15

5 -20 = -15

-15 = -15

-sqrt(10)

5 - 2(-sqrt(10))² = -15

5 -2(10) = -15

5 -20 = -15

-15 = -15