Math question:L If you are good at math, come in

[luvya]

In a certain school, 40 more than 1/3 of all the students are taking a science course and 1/4 of those taking a science course are taking physics. If 1/8 of all the students in the school are taking physics, how many students are in the school?

Show your steps, not interested in just the answer since I have the solution book already.

 

[dighn]

a = total number

(a/3 + 40)/4 = a/8

a = 240

 

beat to it.

 

[minendo]

.

 

[luvya]

Originally posted by: dighn
a = total number

(a/3 + 40)/4 = a/8

a = 240

Ok, why (a/3 + 40)/4 = a/8 ? The solution book shows this step also, but how can you assume them to be equal? I mean there are still a - (a/3 + 40) of students that we don't know whether they take physics class or not.

 

Okay, 1/8 of all the students in the school are taking physics. Also, 1/4 of students taking science are taking physics. So you can see that students taking physics is equal to BOTH 1/8 of students AND 1/4 of science students. Plug the appropriate numbers in, and you're all set.

 

[dighn]

Originally posted by: luvya

Originally posted by: dighn
a = total number

(a/3 + 40)/4 = a/8

a = 240

Ok, why (a/3 + 40)/4 = a/8 ? The solution book shows this step also, but how can you assume them to be equal? I mean there are still a - (a/3 + 40) of students that we don't know whether they take physics class or not.

left side is the number of physics taking students from the first part of the clue => 1/4 of students taking science, student taking science = a/3 + 40

right side is the number of pysics taking studetsn from the second part of the clue => 1/8 of total studetsn a/8

it doesn't matter how many students are not taking physics. you take what the question specifically tell you and put that into an equation

 

[OulOat]

Originally posted by: dighn

Originally posted by: luvya

Originally posted by: dighn
a = total number

(a/3 + 40)/4 = a/8

a = 240

Ok, why (a/3 + 40)/4 = a/8 ? The solution book shows this step also, but how can you assume them to be equal? I mean there are still a - (a/3 + 40) of students that we don't know whether they take physics class or not.

left side is the number of physics taking students from the first part of the clue => 1/4 of students taking science, student taking science = a/3 + 40

right side is the number of pysics taking studetsn from the second part of the clue => 1/8 of total studetsn a/8

it doesn't matter how many students are not taking physics. you take what the question specifically tell you and put that into an equation

The question states that a/3+40 students are taking science, so that means a - (a/3 + 40) is NOT taking ANY science.

 

[bleeb]

That was too easy. Next time, try to post harder problems!! =P

 

[luvya]

Allright, I think I get it now. Thanks.

 

[cain]

damn, its one of the those SAT questions that confuses the sh1t out of you before asking you the real question

 

[cchen]

Originally posted by: luvya
Allright, I think I get it now. Thanks.

damn, you're in college and asking a simple problem you should be able to solve in high school?

 

[dighn]

Originally posted by: cchen

Originally posted by: luvya
Allright, I think I get it now. Thanks.

damn, you're in college and asking a simple problem you should be able to solve in high school?

arts major ?