Pippa has a box containing n pens.

Mathematics

1 answer:

Setler [38]1 year ago

6 0

The possible values of N from the given probability parameters is; N equals 15 or 21

<h3>How to Solve Algebra Problems?</h3>

We are told that;

Number of pens in the box = N

Let the number of red pens be x

Thus; number of black pens = x + 3

Thus;

x + x + 3 = N

x = (N - 3)/2

The probability that she will take a black pen followed by a red pen is;

P(she will take a black pen followed by a red pen) = (x + 3)/N * x/(N - 1)

Plugging in he relevant values and solving for N gives ;

Solving for N gives N equals 15 or 21

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Bill and Mary Ann went to the Viola bakery. Bill bought 5 pies and 7 donuts for $12.65. Mary Ann bought 6 of each for $12.30.

sweet [91]

Answer:

Pies=$0.85

Donuts= $1.20

Step-by-step explanation:

In the equation let p stand for the number of pies and d stand for the number of donuts.

To solve this set up 2 equations, one representing bill and the other representing Mary Ann.

Bill's equation is 5p+7d=$12.65.
Mary Ann's equation is 6p+6d=$12.30

Then solve using a system of equations. Systems of equations can be solved using elimination or substitution. I will use substitution. Solve bill's equation for p. This gives you $p=\frac{12.65-7d}{5}$ . Then, you can substitute that into Mary Ann's equation. This looks like $6\cdot \frac{12.65-7d}{5}+6d=12.3$ . Solve for d. Once you solve d=1.20. Finally, substitute 1.20 back into either Bill's or Mary Ann's for d and solve for p. No matter which equation you use p=0.85.