When setting up the equation you have the initial fee and the hourly fee. The hourly fee is what must be multiplied by the number of hours which is our unknown

6 0

3 years ago

Twenty-eight athletes participate in a 100-meter race. The time of each athlete is measured during the qualification round. The

andriy [413]

The average time of the 20 athletes who did not qualify for the final is 11.2 seconds .

<u>Step-by-step explanation:</u>

Here we have , Twenty-eight athletes participate in a 100-meter race. The time of each athlete is measured during the qualification round. The average time is 11 seconds. The 8 athletes with the fastest time qualified for the final. The average time of these 8 athletes is 10.5 seconds. Let's have equations for this:

$\frac{x_1+x_2+.....+x_2_8}{28} = 11$ where $x_1, x_2, ....., x_2_8$ are athletes

⇒ $x_1 + x_2 + .. + x_2_8 = 11(28)= 308$

⇒ $(x_1 + x_2 + .. + x_8 )+ (x_9+x_1_0+...+x_2_8) = 308$

⇒ $(\frac{x_1 + x_2 + .. + x_8}{8} )(8)+ (\frac{x_9+x_1_0+...+x_2_8}{20} )(20) = 308$

⇒ $10.5(8)+m(20) = 308$ , where m is average time of the 20 athletes who did not qualify for the final.

⇒ $84+m(20) = 308$

⇒ $20m= 224$

⇒ $m=11.2$

∴ The average time of the 20 athletes who did not qualify for the final is 11.2 seconds .

8 0

3 years ago