Data Sufficiency

Plz solve this n explain the same

OA?

Male avg = am = 9.8
female avg = af = 9.1

no of male = nm
no of female = nf

nm / nf = ????????


A
nm = 52
Insuff


B:

(am * nm) + (af * nf)
--------------------- = 9.1
nm + nf


(9.8 * nm) + (9.1 * nf)
--------------------- = 9.1
nm + nf

2 unkown one equn
so Insuff


A+B
(9.8 * nm) + (9.1 * nf)
--------------------- = 9.1
nm + nf
and
nm = 52

solve for nf
and find ratio

so Ans IMO is C

Here is no need to test each statement alone

Combining (1) and (2)
let m be the number of men, f - the number of women

we get
9,8m = summ of men's ages
9,1f = summ of women's ages

(9,8m+9,1f)/(m+f) = 9,3
soving we get
5m=2f
m/f = 2/5

C

why is the answer not B ?

gmatguy16 wrote:why is the answer not B ?

2 unknowns and just 1 equation

4meonly wrote:Here is no need to test each statement alone

Combining (1) and (2)
let m be the number of men, f - the number of women

we get
9,8m = summ of men's ages
9,1f = summ of women's ages

(9,8m+9,1f)/(m+f) = 9,3
soving we get
5m=2f
m/f = 2/5

C

Why C? You don't seem to have used stmt (1). Since only info from (2) is sufficient to get the desired ratio m/f, the OA should be B. Whats the OA?

Ans is C because:

Setting up the equation for I is:

9.8x + 9.1y / 52 -- Not sufficient

Setting up the equation for II is:
9.8x + 9.1y / total = 9.1 -- Not sufficient


But with II using I

9.8x + 9.1y/52 = 9.1

Thus C

using statement b ONLY,

let # of male employees =m
# of female employees = f
9.8 m +9.1 f = 9.3(m+f)
0.5 m = 0.2 f
m/f =2/5 ratio know ,so why is the answer not B.

gmatguy16 wrote:using statement b ONLY,

let # of male employees =m
# of female employees = f
9.8 m +9.1 f = 9.3(m+f)
0.5 m = 0.2 f
m/f =2/5 ratio know ,so why is the answer not B.

OA: B

uups..

Agree with B