Math, asked by kvnmurty, 1 year ago

Given a and b are two natural numbers.

 \frac{290}{a \: b} - \frac{3}{b} - \frac{5}{a } = 1
Calculate
 \frac{a}{b} and \: a + b.


kvnmurty: Use simple algebra. No guessing numbers
Anonymous: Plz Reconsider the Question....
kvnmurty: use factorization

Answers

Answered by Anonymous
1
Heya User,

[tex] \frac{290}{ab} - \frac{3}{b} - \frac{5}{a} = 1 \\\\ =\ \textgreater \ \frac{290}{ab} = \frac{3}{b} + \frac{5}{a} +1\\\\ =\ \textgreater \ \frac{290}{ab} = \frac{3a + 5b + ab}{ab} \\\\ =\ \textgreater \ ab \:[\: 3a + 5b + ab - 290 \:][/tex]

Now, ab ≠ 0;
=> 
[tex]3a + 5b +ab - 290 = 0\\giving \: us:-\ \textgreater \ \\ 3a + 5b +ab = 290;[/tex]

We know that (a,b) > 0;
--> a[ b + 3 ] + 5[ b + 3 ] = 290 + 15 ----> (i)

=> [ a + 5 ][ b + 3 ] = 305

--> Factors of 305 --> 1*305, 5*61

--> Only possible comparison is :->
--> [ a + 5 ] = 61 => a = 56
--> [ b + 3 ] = 5 ==> b = 2;

Hence, [ (a+b) , (a/b) ] = (58,28) <--- Ans.... :)

kvnmurty: but you tried sincerely. very good. Good attempt. thank you
Anonymous: No pair of such Natural no.s that satisfy the Eqn.
Anonymous: Consider 10th last line...
kvnmurty: you did good. but you made a small mistake. . instead of 5b you wrote 4b. that is the reason you couldn't get right answer.
kvnmurty: Check your 4 th step. from top. That's the mistake
kvnmurty: use factorization
Anonymous: oops
Anonymous: Np .. you now know how to solve it
kvnmurty: correct it now. you can EDIT now.
kvnmurty: you hav done well.
Answered by Anonymous
1
290/ab - 3/b - 5/a = 1

→ 290/ab = 3/b + 5/a + 1

→ 290/ab = (3a+5b+ab)/ab

→ 290 = 3a+5b+ab

adding 15 on both sides -

290+15 = 3a+5b+ab+15

→ 305 = a(3+b)+5(3+b)

→ 305 = (a+5)(3+b)

Now we can express 305 as 61×5

→ 61×5 = (a+5)(3+b)

On comparing both sides , we get-

a+5 = 61
→ a = 56

3+b = 5
→ b =2

Now a+b = 56+2 = 58

a/b = 56/2 = 28

___________________________________

kvnmurty: thanks
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