DS-When 1000 children were inoculated with

[sanath.kumar.patro]

When 1000 children were inoculated with a certain vaccine some developed fever and some developed inflammation. How many children developed inflammation but not fever??

1. 880 children developed neither inflammation fever .
2. 20 children developed fever.

THIS IS A QUESTION FROM GMAT PREP.

My approach:-
1. no. of chlren who either got an inflammation or fever or both=1000-880=120
so insufficient

2. 20 chilren got fever
insufficient

combining 1 & 2 we get- 100 children are left that includes- no. of children effected by fever ONLY + no. of children effected by bot FEVER & inflaamation.

So we cant determine the number of children who are effected ony by the inflammation. Hence E
but the OA is C.
Am i missing something??
Can the instructors help, please????

[oren.yomorta]

By saying some developed disease a and others developed disease b, the writers are telling us non developed both...

Hope that helps some...

[pranabiitkgp]

F-Oonly fever but not inflamation
x-having both
I - only inflamation.
F+x+I = 120
F+x = 20
So I = 100

[RonPurewal]

When 1000 children were inoculated with a certain vaccine some developed fever and some developed inflammation. How many children developed inflammation but not fever??

1. 880 children developed neither inflammation fever .
2. 20 children developed fever.

THIS IS A QUESTION FROM GMAT PREP.

My approach:-
1. no. of chlren who either got an inflammation or fever or both=1000-880=120
so insufficient

2. 20 chilren got fever
insufficient

combining 1 & 2 we get- 100 children are left that includes- no. of children effected by fever ONLY + no. of children effected by bot FEVER & inflaamation.

So we cant determine the number of children who are effected ony by the inflammation. Hence E
but the OA is C.
Am i missing something??
Can the instructors help, please????

use the double set matrix:
---------------------FEVER-----NO FEVER-----TOTAL
INFLAMMATION
NO INFLAMM.
TOTAL

statement (1):
---------------------FEVER-----NO FEVER-----TOTAL
INFLAMMATION
NO INFLAMM.--------------------880-----------
TOTAL-------------------------------------------1000
insufficient

statement (2):
---------------------FEVER-----NO FEVER-----TOTAL
INFLAMMATION
NO INFLAMM.
TOTAL----------------20-----------980----------1000
insufficient (although we can fill in 1000 - 20 = 980)

together:
---------------------FEVER-----NO FEVER-----TOTAL
INFLAMMATION-----------------100
NO INFLAMM.--------------------880-----------
TOTAL----------------20----------980----------1000
sufficient; 100 is the desired answer.