FIND the number of combinations 8C2

8c2 = 28

Step-by-step explanation:

You can plug this into your calculator (on a TI-84, it's MATH -> PRB -> 3) as 8 nCr 2.

Let's try to understand what the output means, though! The nCr function is based on Pascal's Triangle (see the attachment for a picture).

When we do 8 choose 2, we are basically thinking about having 8 possible values and 2 spots to fit them in, and we don't care about what order they're in. The probability of this is 8*7 / 2 = 28. Our answer makes sense!

the first question mark is 6 and the second question mark is 26 (the square root)

step-by-step explanation:

use an equation of ratios to determine the amount of gas needed to fill the tank.

    0.2             0.8

  =    

288.75             x

                                                              231 gal

so, 0.2x = (0.8)(288.75 gal), and x = = 1155 gal.

                                                                0.2

it would take 1155 gal. to fill the tank.

the cost would be

1155 gal         $3

* = $3465   (answer)

      1           1 gal

hope this you