A petrol-diesel solution, containing 40% petrol is mixed with another solution M, of unknown concentration in the ratio 2: 3 by volume. This mixture is then mixed with a double quantity of another 40% petrol solution, to obtain the final mixture. The final mixture has a petrol concentration of 45%. What is the petrol concentration in the solution M

alligation formula with respect to petrol concentration.

Step 1
40% ( 2 parts) ____________a% ( 3 parts)
... ..............x %(5 parts)
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Step 2
x % ( 5 parts) _________40 %(10 parts)
............... 45%(15 parts)
45--40==5 .................. x--45
..............5/5 === (x--45)/10
x = 55 %, .....putting in Step 1
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40% (2 parts) ________ a% ( 3 parts)
................55%( 5 parts)
(a--55) .................. ( 55--40==15 )
.....(a--55)/2 == 15/3 =5

so __a = 65 % petrol in solution M.

Let petrol-diesel quantity=2 lit. &and; Another solution M=3 lit. (2:3 ratio is given) &amp; Assume petrol conc. In M is x%.<br>Total mixture= 5 lit.<br>Now add twise of total mixture (5*2=10 lit.)<br>Of petrol-diesel mixture (2 lit. + 10 lit. = 12 lit.)<br>Now total is 15 lit.(12 lit petrol-diesel &amp; 3 lit.of solution M)<br>Ratio is 12:3 = 4:1.<br>Now,<br>40%. ---------&gt;45%<br>

let the 40% solution be N
2(N) + 3(M) + 6(N)
6N : 3M
2N : 1M
avg ( 40,40,M) = 45
m comes down to 65