Addison High School’s senior class has 160 boys and 200 girls. If 75%

Question

Addison High School’s senior class has 160 boys and 200 girls. If 75% of the boys and 84% of the girls plan to attend college, what percentage of the total class plan to attend college?

A. 75
B. 79.5
C. 80
D. 83.5
E. 84

Kudos for a correct  solution .

ENGRTOMBA2018 · Answer

Number of boys attending the party : 0.75*160 = 120

number of girls attending the party: 0.84*200 = 168

Total attending = 120+168 = 288

Total people = 160+200 = 360

% of people attending = 288/360 = 80%. C is the correct answer

mejia401 · Answer

Total students = 360
Male students attending college = 120
Female students attending college = 164, 84 (percent) doubled

\frac{288}{360}=\frac{8}{10} 
Option C.

Alternative method is weighted average. A, D and E are wrong since the average shouldn't favor one side or the other too much. Between B and C...
160/360 reduces to 4/9 of the students are males, and therefore 5/9 are females.
 = \frac{{4*75+5*85}}{9} 
= 80
Option C.

KS15 · Answer

75% of 160 boys=120 boys
84% of 200 girls=168 girls
Reqd %=(120+168)/360*100=80%
Answer C

VenoMfTw · Answer

IMO : C

75% of the boys plan to attend college = 75% of 160 
= 3/4 * 160 
= 120

84% of the girls plan to attend college = 84% of 200
= 168

Total no of students = 160+200 = 360
Total no. of students plan to attend college = 120+168 = 288

percentage of the total class plan to attend college =  \frac{288}{360}  * 100
= 80%

noTh1ng · Answer

Not difficult at all, however the many calculations took me well more than 2 minutes...

CounterSniper · Answer

total for boys + girls in percentage =>288/360 *100 = 80%

Bunuel · Answer

GROCKIT OFFICIAL SOLUTION:

84 is an obscure number. When you see obscure numbers, that is another sign that you may want to look for an approximating shortcut.

Firstly, we should eliminate the overtly incorrect choices. This will be (A) 75 (since that’s the low extreme) and (E) 84 and (D) 83.5 (since they are both essentially equal to the high extreme).

Secondly, find the average of the given percents. Since there are more girls than boys, we know that the weighted average will be closer to the girls’ percent than the boys’ percent. By finding 79.5% as the mean of 75% and 84%, we are given the low extreme. Again, we recognize the weight placed on 84%, making the answer higher than 79.5.  (C) 80 it is!

(For similar questions in the future where we actually need to calculate, we could drop the extra “0” from 160 and 200. The ratio of 16:20 is the same (4:5), and the calculation is much easier.)

jasimuddin · Answer

75% of 180=120
84% of 200=168
(120+168)*100/(180+200)=80%
ans: c

bumpbot · Answer

Automated notice from GMAT Club BumpBot: 

A member just gave Kudos to this thread, showing it’s still useful. I’ve bumped it to the top so more people can benefit. Feel free to add your own questions or solutions.

 This post was generated automatically.

Addison High School’s senior class has 160 boys and 200 girls. If 75%

Prep Toolkit

Top 5 GMAT Debrief Videos

615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

745 with Only Self-Prep and GMAT Club

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia

My Rewards

GMAT Problem Solving (PS) Questions

Addison High School’s senior class has 160 boys and 200 girls. If 75%

Prep Toolkit

615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

745 with Only Self-Prep and GMAT Club

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia

My Rewards