Each student in a certain class is considered intermediate o

[fskilnik@GMATH]

GMATH practice exercise (Quant Class 6)

Each student in a certain class is considered intermediate or strong, but not both. The average of the grades of the strong students is 6.3 points, exactly two points above the average of the grades of the intermediate students. What is the percentage of strong students in this class, if the average of all students grades in this class is half point below the average of the grades of the strong students?

(A) 60%
(B) 65%
(C) 70%
(D) 75%
(E) 80%

Answer: [spoiler]___(D)__[/spoiler]

[fskilnik@GMATH]

GMATH practice exercise (Quant Class 6)

Each student in a certain class is considered intermediate or strong, but not both. The average of the grades of the strong students is 6.3 points, exactly two points above the average of the grades of the intermediate students. What is the percentage of strong students in this class, if the average of all students grades in this class is half point below the average of the grades of the strong students?

(A) 60%
(B) 65%
(C) 70%
(D) 75%
(E) 80%

$$?\,\, = \,\,\frac{{100}}{{100 + x}}$$
$$\left( {{\text{Alligation}}} \right)\,\,\,\,?\,\, = \,\,\frac{{100}}{{100 + x}}\,\, = \,\,\frac{{5.8 - 4.3}}{{6.3 - 4.3}}\,\, = \,\,\frac{{1.5}}{2}\,\, = \,\,\underleftrightarrow {\frac{1}{{10}}\left( {\frac{{15}}{2}} \right) = 0.75}\,\, = \,\,75\% $$

The correct answer is (D).


We follow the notations and rationale taught in the GMATH method.

Regards,
Fabio.