Ineed with this problem ! evaluate 3/7r + 5/8s when r=14 and s=8.

11

Step-by-step explanation:

It is given that:

r = 14 & s = 8

Plug in the corresponding numbers to the corresponding variables:

(3/7)(14) + (5/8)(8)

Solve. Remember to simplify. Do multiplication & division first, then add:

(3/7)(14) + (5/8)(8)

(3 * 14)/7 + (5 * 8)/8

(3 * 2) + 5

(6) + 5

11

11 is your answer.

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Explanation:

Let's name the friends A, B, C

If person A is first, then B or C could be second and third.

So we have ABC or ACB as two possible outcomes.

If B is first, then either A is second or C is second. Meaning we have BAC or BCA.

If C is first, then we have CAB or CBA

Overall here are the 6 different ways to have the runners finish

Note how for the first slot we have 3 ways to pick the winner. Then after that selection is made, we have 2 choices left, then 1 choice for third place. Therefore, 3*2*1 = 6 different outcomes are possible.

We can use the factorial operation on the calculator to do this with one button press, so we'd say 3! = 6. The exclamation mark means "multiply from 3 down to 1, counting down the whole time".

Another example of a factorial is:

5! = 5*4*3*2*1 = 120