Test Your Basic Concept....................

Algebra Level 2

Solve It:-


The answer is 6.

This section requires Javascript.
You are seeing this because something didn't load right. We suggest you, (a) try refreshing the page, (b) enabling javascript if it is disabled on your browser and, finally, (c) loading the non-javascript version of this page . We're sorry about the hassle.

3 solutions

Pham Khanh
Apr 23, 2016

( a + b + c ) ( 1 a + 1 b + 1 c ) = 6 × 3 2 = 9 \small (a+b+c)(\frac{1}{a}+\frac{1}{b}+\frac{1}{c})=6 \times \frac{3}{2}=9 a a + a b + a c + b a + b b + b c + c a + c b + c c = 9 \iff \frac{a}{a}+\frac{a}{b}+\frac{a}{c}+\frac{b}{a}+\frac{b}{b}+\frac{b}{c}+\frac{c}{a}+\frac{c}{b}+\frac{c}{c}=9 ( a b + a c + b a + b c + c a + c b ) + ( a a + b b + c c ) = 9 \iff \large (\color{#3D99F6}{\frac{a}{b}+\frac{a}{c}+\frac{b}{a}+\frac{b}{c}+\frac{c}{a}+\frac{c}{b}})+(\frac{a}{a}+\frac{b}{b}+\frac{c}{c})=9 ( a b + a c + b a + b c + c a + c b ) + 1 + 1 + 1 = 9 \iff \Large (\color{#3D99F6}{\frac{a}{b}+\frac{a}{c}+\frac{b}{a}+\frac{b}{c}+\frac{c}{a}+\frac{c}{b}})+1+1+1=9 a b + a c + b a + b c + c a + c b = 9 1 1 1 = 6 \iff \LARGE \color{#3D99F6}{\frac{a}{b}+\frac{a}{c}+\frac{b}{a}+\frac{b}{c}+\frac{c}{a}+\frac{c}{b}}=9-1-1-1=\Huge \color{#20A900}{\boxed{\color{#3D99F6}{6}}}

Abdul Lah
Sep 29, 2014

since a +b +c = 6 now a/b+a/c+b/a+b/c + c/b+ c/a = a(1/b+1/c)+b(1/a+1/c)+c(1/b+1/a) = a(3/2-1/a)+b(3/2-1/b)+c(3/2-1/c) =3/2(a+b+c)-3 =3/2(9) - 3 = 6

Tan Wee Kean
Aug 3, 2014

Good problem but you can guess a = 2 , b = 2 , c = 2 a = 2, b = 2, c = 2

A proper solution would be to add a a , b b , c c \frac { a }{ a } ,\frac { b }{ b } ,\frac { c }{ c } . Then, the desired value will increase by 3 and can be obtained by multiplying ( a + b + c ) ( 1 a + 1 b + 1 c ) = 9 9 3 = 6 (a+b+c)(\frac { 1 }{ a } +\frac { 1 }{ b } +\frac { 1 }{ c } )=9\\ 9-3=6

0 pending reports

×

Problem Loading...

Note Loading...

Set Loading...