Bella keeps a supply of red, blue, and black pens in a drawer. The drawer has 14 red pens, 18 blue pens, and 10 black pens. If Bella wants a red pen, what is the minimum number of pens she has to pull out from the drawer to make sure she gets a red pen?
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To make sure Bella gets a red pen, she needs to pull out a minimum of 1 red pen from the drawer.
To find the minimum number of pens Bella has to pull out to guarantee she gets a red pen, we first need to determine the worst-case scenario. This occurs when she pulls out all the other colored pens before getting a red one.
Bella has a total of 14 red pens, 18 blue pens, and 10 black pens, which means she has a total of 14 + 18 + 10 = 42 pens in the drawer.
The worst-case scenario would be if Bella pulls out all the blue and black pens before getting a red pen. Therefore, the minimum number of pens she has to pull out is the number of blue pens plus the number of black pens, which is 18 + 10 = 28 pens.
Therefore, Bella has to pull out a minimum of 28 pens to make sure she gets a red pen.