Problema GMAT Quant 16/06/14 (PS) (>700)

[Recobita]

Quant (PS) (>700)

After M students took the test, there was a total of 64% of correct answers. If the test contains 50 questions, what is the least number of questions that the next student have to get right to bring the total of correct answers to 70%?

(A) 3M + 20
(B) 3M + 35
(C) 4M + 15
(D) 4M + 20
(E) 4M + 45

[Recobita]

Quant (Problem Solving) (>700)

After M students took the test, there was a total of 64% of correct answers. If the test contains 50 questions, what is the least number of questions that the next student have to get right to bring the total of correct answers to 70%?

(A) 3M + 20
(B) 3M + 35
(C) 4M + 15
(D) 4M + 20
(E) 4M + 45

Solución propuesta:

respuesta: show

Número total de respuestas correctas con M estudiantes= 64%*50*M=32M
Número total de respuestas correctas con M+1 estudiantes= 70%*50*(M+1)=35M+35
Número mínimo de respuestas que debe acertar= 35M+35-32M=3M+35

La respuesta correcta es (B)