Re: Algebra problem, dvds

Quote:

Originally Posted by

**Sewilliams13** Phil has three times as many DVDS as sam has. Even after Phil gives Sam 6 DVDs, he still has 16 more DVDs than Sam has. What was the original number of DVDs that Phil had?

I set this up like so,

P=3*S

P-6=16+S+6

(S=Sam)

How do I solve this? Any answers appreciated!(Worried)

Looks good. Now, since P= 3S, you can replace P in the second equation 3S: 3S- 6= 16+ S+ 6= S+ (16+ 6)= S+ 22.

If you add 6 to both sides, that gives you 3S- 6+ 6= S+ 22+ 6 or 3S= S+ 28. Can you finish that?

Re: Algebra problem, dvds

Quote:

Originally Posted by

**HallsofIvy** Looks good. Now, since P= 3S, you can replace P in the second equation 3S: 3S- 6= 16+ S+ 6= S+ (16+ 6)= S+ 22.

If you add 6 to both sides, that gives you 3S- 6+ 6= S+ 22+ 6 or 3S= S+ 28. Can you finish that?

I can finish that, to end up getting 14=s. Thank you very much! What a simple blunder-_- All that frustration for nothing! My SAT book gave this strategy, which threw me off.

P=3S P/3=S

P-6=16+P/3+6

P-6=48+P+18/3

3P-18=48+P+18

2P=84

P=42.

^^The book (Grubers 2013) Is trying to say that this is a simpler strategy. I disagree. Thanks for the wonderful help!

Re: Algebra problem, dvds

Quote:

Originally Posted by

**Sewilliams13** I can finish that, to end up getting 14=s. Thank you very much! What a simple blunder-_- All that frustration for nothing! My SAT book gave this strategy, which threw me off.

P=3S P/3=S

P-6=16+P/3+6

P-6=48+P+18/3

3P-18=48+P+18

2P=84

P=42.

^^The book (Grubers 2013) Is trying to say that this is a simpler strategy. I disagree. Thanks for the wonderful help!

Well, it is simpler....since you're asked how many DVD's Phil has (not S); solution leads directly to Phil;

doing it the other way leads to DVD's Sam has; you then need to substitute to get Phil.

Btw, this: P-6=48+P+18/3

requires brackets: P-6=(48+P+18)/3

Re: Algebra problem, dvds

Ahh that makes so much more sense with brackets!(they were not in the book ?) Thank you!!