GMAT prep PS question
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Lets have the Total number of students as T=1000
then M= 480 and F=520.
Now M and F who are > 25 yrs are
M= 480*40/100=192
F=520*1/5=104
Hence Probability,P=192/1000 + 104/1000 = 296/1000 = 0.296=0.3 approx
D.) = 0.3
- Deepak
then M= 480 and F=520.
Now M and F who are > 25 yrs are
M= 480*40/100=192
F=520*1/5=104
Hence Probability,P=192/1000 + 104/1000 = 296/1000 = 0.296=0.3 approx
D.) = 0.3
- Deepak
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I second for 0.7
40/100 of 48 male=19.2 greater than 25
20/100 of 52 female=10.4 greater than 25
19.2+10.4=29.6 greater than 25
So appr 70% is less than 25
And the probability is 70 out 100=0.7
40/100 of 48 male=19.2 greater than 25
20/100 of 52 female=10.4 greater than 25
19.2+10.4=29.6 greater than 25
So appr 70% is less than 25
And the probability is 70 out 100=0.7
The more you look, the more you see.
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Answer is .70, first solution is correct except for it is solved for the probability of someone greater than 25 and the question asks for less than 25.
For a quick way use a class size of 1000
M=480; M<25=480*.6=288
F=520; F<25=520*.8=416
M+F/1000=704/1000=.704
Normally using a value of 100 works well in percent questions but when you get decimals for values when you need integers (i.e. People) just move the decimal to the right one place.
For a quick way use a class size of 1000
M=480; M<25=480*.6=288
F=520; F<25=520*.8=416
M+F/1000=704/1000=.704
Normally using a value of 100 works well in percent questions but when you get decimals for values when you need integers (i.e. People) just move the decimal to the right one place.
- gmat740
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let the class strength be 100
Males = 48
Females =52
now, 40% of M are 25+
so, 60% of M less than 25
thus, 0.6*48 = 28.8 males = 29 M
Similarly,
20% of 52 F are 25+
so, 80% of 52 F are less than 25 yrs
thus,
0.8*52 = 42 F less than 25
total people less than 25 = 29M+42 F = 71
total = 100
Prob = 71/100 = 0.71
Hope this Helps
Males = 48
Females =52
now, 40% of M are 25+
so, 60% of M less than 25
thus, 0.6*48 = 28.8 males = 29 M
Similarly,
20% of 52 F are 25+
so, 80% of 52 F are less than 25 yrs
thus,
0.8*52 = 42 F less than 25
total people less than 25 = 29M+42 F = 71
total = 100
Prob = 71/100 = 0.71
Hope this Helps