Data Sufficiency

In an office that employees 120 people, m% of the employees are male, and c% of the employees are members of the custodial staff. How many employees are females who are not members of the custodial staff?

1) m + c = 50

2) The number of female employees who are members of the custodial staff is four

E IMO

Yeah that's the answer.
I don't understand the reasoning; could you explain?

winniethepooh wrote:In an office that employees 120 people, m% of the employees are male, and c% of the employees are members of the custodial staff. How many employees are females who are not members of the custodial staff?

1) m + c = 50

2) The number of female employees who are members of the custodial staff is four

Number of Males = (m/100)*120 = 1.2*m
Number of Females = 120 - 1.2m

Number of members of Custodial Staff = (c/100)*120 = 1.2*c
Number of members of non-custodial Staff = 120-1.2*c

Number of females in the non-custodial staff = ?

1) m + c = 50

The value of (m,c) can be (20,30) or (30,20) or (10,40) or (40,10) ...
Hence Insufficient

2) The number of female employees who are members of the custodial staff is four

Number of females = 120 - 1.2m
Number of females in custodial staff = 4
Number of females in non-custodial staff = Unknown

so Unknown + 4 = 120-1.2m

Hence, Insufficient!

Taking both 1 and 2, We have two equations and three unknowns(in bold)
Unknown + 4 = 120-1.2m and
m + c = 50

IMO Answer : E

Males (m) + Females(f) = 120

m+f = 100%

custodial staff (in 120) = c %

asked females who are not custodial staff.

Statement 1:

m+c = 50

male % and 'c' can take any value that add up to 50. Insufficient alone

Statemnet 2:

female + custodial staff = 4.

it gives us nothing about total no of females or today custodial staff.

Together,

Even together, we can't find the total female % or the custodial staff % which is needed to find number of females who are not custodial staff.

At this stage of my prep I make very stupid mistakes.
No wonder I score really low in quant!

It's E because you know the males who are custodial staff from 1) and females who are custodial staff from 2). There are still two holes to fill: males who aren't custodial staff and females who aren't custodial staff.