prepp wrote:Thanks for the explanation Mitch.
Usually, the approach for DS is that we evaluate each statement independently.
Please can you explain solving this question just by evaluating the q stem with statement 2?
Thanks a lot!
In a group of 1000 people, each person is either left-handed or right-handed but not both. 80% of the females are left-handed, and 84% of the right-handed people are male. How many people are right-handed?
1) There are 600 males in the group
2) There are 180 left-handed males in the group
This is an EITHER/OR group question.
Every person is EITHER male OR female.
Every person is either LEFT-HANDED or RIGHT-HANDED.
For an EITHER/OR group problem, use a GROUP GRID to organize the data.
Put all of the information in terms of ONE VARIABLE.
From the question stem:
Total people = 1000.
Let total females = 100f.
Since 80% of the females are left-handed, left-handed females = 80f and right-handed females = 20f.
Here's the grid so far:
_______________M________F_______Total
L:______________________80f
R:______________________20f________
total:__________________100f______1000
Since 84% of the right-handed people are male, right-handed females -- 20f in the grid above -- account for 16% of the total number of right-handed people:
20f = .16(total right-handed)
Total right-handed = 20f/.16 = 2000f/16 = 125f.
Completing the middle row of the grid, we get:
_______________M________F_______Total
L:______________________80f
R:____________105f______20f_______125f
total:__________________100f______1000
Statement 2: There are 180 left-handed males in the group.
Inserting this information into the grid, we get:
_______________M________F_______Total
L:____________ 180______80f_____180+80f
R:____________105f______20f_______125f
total:__________________100f______1000
The rightmost column implies the following:
(180+80f) + 125f = 1000.
205f = 820
f=4.
Thus, total right-handed = 125f = 125*4 = 500.
SUFFICIENT.
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