# did this equation b+3+b=68

• Sep 27th 2012, 09:23 PM
Rosestar
did this equation b+3+b=68
.....for this problem and I don't kno what am I doing wrong. I did it jus like Mark showed me >.>

Mr. Alfaro has 3 times as many Pre-Algebra students than Beginning Algebra students. If Mr. Alfaro has a total of 72 students, find the number of students in each course.

a) Write the equation you would use to solve this problem, using http://www.imathas.com/cgi-bin/mimetex.cgi?%7Bb%7D as the number of Beginning Algebra students. ___________

b) After solving the equation, how many Beginning Algebra students does Mr. Alfaro have? __________

c) After solving the equation, how many Pre-Algebra students does Mr. Alfaro have? __________
• Sep 27th 2012, 09:32 PM
MarkFL
Re: did this equation b+3+b=68
What two equations do you have from the information given?
• Sep 27th 2012, 09:47 PM
Rosestar
Re: did this equation b+3+b=68
I got 3+b+b=72
then i subtract -3 from both side
got b+b= 69/2
b=34.5 then I did 3+34.5 =37.7

so I got B= 34.5 and P =37.5 both equal to 72
• Sep 27th 2012, 09:49 PM
Rosestar
Re: did this equation b+3+b=68
well now I'm working with different numbers but same concept.
• Sep 27th 2012, 09:52 PM
MarkFL
Re: did this equation b+3+b=68
Let \$\displaystyle p\$ be the number pf Pre-Algebra students,a dn \$\displaystyle b\$ be the number of Beginning Algebra students.

From the statement "Mr. Alfaro has 3 times as many Pre-Algebra students than Beginning Algebra students" we may write:

\$\displaystyle p=3b\$

You see this is a bit different from the previous problems because we are give that one quantity is a certain multiple of the other rather than being told one is a certain amount more or less than the other.

From the statement "Mr. Alfaro has a total of 72 students" we may write:

\$\displaystyle p+b=72\$

Now, what should you do next?
• Sep 27th 2012, 09:53 PM
Rosestar
Re: did this equation b+3+b=68
but formy first equation I did... b+3+b=68
-3 -3
_____________
b + b = 65
2b = 65
b=32.5 ; /
• Sep 27th 2012, 09:55 PM
Rosestar
Re: did this equation b+3+b=68
Quote:

Originally Posted by MarkFL2
Let \$\displaystyle p\$ be the number pf Pre-Algebra students,a dn \$\displaystyle b\$ be the number of Beginning Algebra students.

From the statement "Mr. Alfaro has 3 times as many Pre-Algebra students than Beginning Algebra students" we may write:

\$\displaystyle p=3b\$

You see this is a bit different from the previous problems because we are give that one quantity is a certain multiple of the other rather than being told one is a certain amount more or less than the other.

From the statement "Mr. Alfaro has a total of 72 students" we may write:

\$\displaystyle p+b=72\$

Now, what should you do next?

3b+b=72
• Sep 27th 2012, 09:58 PM
MarkFL
Re: did this equation b+3+b=68
Yes, so what do you find when you solve for b?
• Sep 27th 2012, 10:01 PM
Rosestar
Re: did this equation b+3+b=68
Quote:

Originally Posted by MarkFL2
Yes, so what do you find when you solve for b?

b=18
• Sep 27th 2012, 10:13 PM
MarkFL
Re: did this equation b+3+b=68
Correct, so what must p be?
• Sep 27th 2012, 10:19 PM
Rosestar
Re: did this equation b+3+b=68
Quote:

Originally Posted by MarkFL2
Correct, so what must p be?

P=54
• Sep 27th 2012, 10:40 PM
MarkFL
Re: did this equation b+3+b=68
Yes. Good work!