Data Sufficiency

Each of the students in a certain class received a single grade of P,F, or I.
What percent of students in the class were females ?

(1) Of those who received a P , 40 percent were females.
(2) Of those who received an F or I, 80 percent were males.

IMO:E

Can you please explain.

Hi,

Each of the students in a certain class received a single grade of P,F, or I.
What percent of students in the class were females ?

(1) Of those who received a P , 40 percent were females.
(2) Of those who received an F or I, 80 percent were males.

From 1) Out of people who received P, 40% were female - Insuff
From 2) Out of peolple who received F/I, 20% were female - Insuff

1+2 - we still do not know how many percent of people received P,F and I (Ratio of P:F:I is unknown)
Hence cannot conclude the %male/%female

IMO:E

Hope it helped!

rppala90 wrote:Each of the students in a certain class received a single grade of P,F, or I.
What percent of students in the class were females ?

(1) Of those who received a P , 40 percent were females.
(2) Of those who received an F or I, 80 percent were males.

Question: What is the ratio of females to males?

This is a weighted average question.
Statement 1: P = 40% female.
Statement 2: F+I = 20% female.

Without knowing what percent of ALL the grades (P+F+I) were female, we cannot determine F:M.

To illustrate:
Let P = 50 and F+I = 50.
Female P = .4(50) = 20.
Female (F+I) = .2(50) = 10.
Total females = 20+10 = 30.
Total males = 100-30 = 70.
F:M = 3:7.

Let P = 90 and F+I = 10.
Female P = .4(90) = 36.
Female (F+I) = .2(10) = 2.
Total females = 36+2 = 38.
Total males = 100-38 = 62.
F:M = 38:62 = 19:31.

Since F:M can be different values, insufficient.

The correct answer is E.

I did some awful calculation and got C but then yes without Total no. of students or total percentage of P F I we can not evaluate female percentage.

so answer E