Data Sufficiency

Can this be solved using the Double Matrix Method?[/img]

J>=100
French=F
F/25 both F and J
to find if F>J??
a)16 study both F and J
F/25=16 ->F=400
J can be 101 or 500
Insufficient
b)J/10 = F/25 -> F=5J/2. Thus F>J
Sufficient
IMO B

@MBACRACKER

Not sure why you want to use the matrix here. Matrix is used in such problems where there each column in mutually exclusive to another column

and the same with the row.

for example if the problem were about two languages and people either study or don't study then we can make a matrix as follows

col1 = Study jap Col2 = doesn't study jap

row1 = Study french row3 = doesn't study french

as you have see col1,col2 and row1,row2 are always mutually exclusive.

This problem we don't have such a scenario of not studying or anything we are only discussing the number of students who study jap, french or both

so its better that you use the method that cans described.

Here is a video solution that might be of help:

https://www.gmatquantum.com/shared-posts ... lem11.html

Dabral