15) Bob has 12 black pen, 14 red pen, 15 green pens, 24 blue pens and 3 boxes of

yellow pens. If the Mean and Median are 16 and 15 respectively, what is the

number of yellow pens in each box?

13, 16, 18

Step-by-step explanation:

Sabemos que podemos calcular el total de plumas amarillos, por medio de la media.

16 = (12 + 14 + 15 + 24 + x + y + z) / 7

16 * 7 = 12 + 14 + 15 + 24 + x + y + z

112 = 65 + x + y + z

x + y + z = 112-65

x + y + z = 47

sabemos que la mediana es el valor medio, y que ese 46 debe dividirse entre 3 valores porque son 3 cajas, entonces debemos buscar los números adecuados para el valor 15 esté en la mitad, es decir de cuarto.

Sin meter los valores nuevos, el ranking sería así:

12

14

15

24

el 15 esta de tercero, para que quede de cuarto, debe tener dos valores por debajo y un por arriba, así:

X

12

14

15

y

z

24

Por lo tanto, valores mayores a 15 serían por ejemplo y = 16 y z = 18:

16 + 18 = 34

x = 47-34 = 13

quedaría:

12

13

14

15

dieciséis

18 años

24

Si recalculamos la media:

m = (12 + 14 + 15 + 24 + 13 + 16 + 18) / 7 = 16

yes yes yes yes yes yes yes yes yes

starting with:    

5 + x - 12 = 2x - 7   

5 + x - 12 - x = 2x - 7 - x (subtract x from both sides)   

5 - 12 = x - 7 (combine and cancel x's from both sides)   

5 - 12 + 7 = x - 7 + 7 (add 7 to both sides)   

0 = x (add numbers together on both sides)       

so in order for the equation to be true, x must be 0.   

trying x = -0.5   

5 + x - 12 = 2x - 7 (original equation)   

5 + -0.5 - 12 = 2(-0.5) - 7 (plug in value of x)   

5 + -0.5 - 12 = -1 - 7 (did multiplication)   

-7.5 = -8 (did addition on both sides)       

since -7.5 is obviously not equal to -8, the value of -0.5 for x is wrong.   

trying x = 0   

5 + x - 12 = 2x - 7 (original equation)   

5 + 0 - 12 = 2(0) - 7 (plug in value of x)   

5 + 0 - 12 = 0 - 7 (did multiplication)   

-7 = -7 (did addition on both sides)       

since -7 equals -7, that demonstrates that the value of 0 for x is correct.   

trying x = 1   

5 + x - 12 = 2x - 7 (original equation)   

5 + 1 - 12 = 2(1) - 7 (plug in value of x)   

5 + 1 - 12 = 2 - 7 (did multiplication)   

-6 = -5 (did addition on both sides)       

since -6 is obviously not equal to -5, the value of 1 for x is wrong.