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bmwhype2
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A, B, C are positive a^2 + c^2 = 202 What is the value of b 12 Nov 2007, 12:11
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A, B, C are positive
a^2 + c^2 = 202
What is the value of b - a - c?

1. b^2 + c^2 = 225
2. a^2 + b^2 = 265

Please exaplin your answers.



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A, B, C are positive a^2 + c^2 = 202 What is the value of b 12 Nov 2007, 12:58
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bmwhype2
A, B, C are positive
a^2 + c^2 = 202
What is the value of b - a - c?

1. b^2 + c^2 = 225
2. a^2 + b^2 = 265

Please exaplin your answers.
Show more


A for me.

1.
a^2+c^2=202
b^2+c^2=225

minus them

b^2-a^2=23----> (b-a)(b+a)=23. b=12 and a=11
then
c^2=202-a^2=81 --- > c=9
12-11-9=-8

2.
a^2 + c^2 = 202
a^2 + b^2 = 265

minus them

b^2-c^2=63----> (b-c)(b+c)=63, here b=32 c=31 or b=8 c=1 thus not suff.

i could not figure out any other method to solve it.
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A, B, C are positive a^2 + c^2 = 202 What is the value of b 12 Nov 2007, 14:02
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bmwhype2
A, B, C are positive
a^2 + c^2 = 202
What is the value of b - a - c?

1. b^2 + c^2 = 225
2. a^2 + b^2 = 265

Please exaplin your answers.

A for me.

1.
a^2+c^2=202
b^2+c^2=225

minus them

b^2-a^2=23----> (b-a)(b+a)=23. b=12 and a=11
then
c^2=202-a^2=81 --- > c=9
12-11-9=-8

2.
a^2 + c^2 = 202
a^2 + b^2 = 265

minus them

b^2-c^2=63----> (b-c)(b+c)=63, here b=32 c=31 or b=8 c=1 thus not suff.

i could not figure out any other method to solve it.
Show more


Stmt one is Insuff

(b-a)(b+a)= 23 is correct but there are millions of solutions for b and a not just b=12 and a=11. A quick example would be b=sqrt(423) and a=20.

If you have two variables then you need two seperate equations with the same variables to solve. So since we have 3 variables we need 3 seperate equations to solve.

Ans C.
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A, B, C are positive a^2 + c^2 = 202 What is the value of b 12 Nov 2007, 22:34
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bmwhype2
A, B, C are positive
a^2 + c^2 = 202
What is the value of b - a - c?

1. b^2 + c^2 = 225
2. a^2 + b^2 = 265

Please exaplin your answers.
Show more


I'm getting C.

stat 1: subtracting a^2 +c^2 = 225 from stat 1 gives us b^2 - a^2 = 23. No good. Insuff.

Stat 2: subtracting a^2 +c^2 = 225 from stat 2 gives us b^2 - c^2 = 63. No good. Insuff.

Together: b^2 + c^2 = 225 (from stat 1) & b^2 - c^2 = 63(see stat 2 above). Adding these two gives us b^2 = 144, which means b = 12 (cannot be -12 due to the stem). Similarly we can solve to get A = 11 and C = 9. Thus, the value of b - a - c can be determined. Suff.



Archived Topic
Hi there,
This topic has been closed and archived due to inactivity or violation of community quality standards. No more replies are possible here.
Where to now? Join ongoing discussions on thousands of quality questions in our Quantitative Questions Forum
Still interested in this question? Check out the "Best Topics" block above for a better discussion on this exact question, as well as several more related questions.
Thank you for understanding, and happy exploring!