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goldenfox [79]
2 years ago
13

En un examen de admisión de 120 preguntas, cada respuesta correcta vale 2 puntos y por cada incorrecta se quita medio punto. Un

postulante respondió todas las preguntas obteniendo 80 puntos. ¿Cuántas preguntas respondió mal? :/
Mathematics
1 answer:
padilas [110]2 years ago
6 0

Answer:

Respondió mal 64 preguntas.

Step-by-step explanation:

De acuerdo a la información proporcionada puedes plantear las siguientes ecuaciones:

x+y=120 (1)

2x-0,5y=80 (2)

x es el número de preguntas correctas

y es el numero de preguntas incorrectas

Primero debes despejar "x" en (1):

x=120-y (3)

Después, debes reemplazar (3) en (2):

2(120-y)-0,5y=80

240-2y-0,5y=80

240-80=2,5y

160=2,5y

y=160/2,5

y=64

Ahora puedes reemplazar el valor de "y" en (3) para encontrar el valor de "x":

x=120-y

x=120-64

x=56

De acuerdo a esto, la respuesta es que el postulante respondió mal 64 preguntas.

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