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Maths Puzzle
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A can contains a mixture of two liquids A and B is the ratio 7 : 5. When 9 litres of mixture are drawn off and the can is filled with B, the ratio of A and B becomes 7 : 9. How many litres of liquid A was contained by the can initially
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- See the ratio of A = 7, check the options which are divisible by 7, 21 is there, simple tricky way.
- 9 years agoHelpfull: Yes(5) No(1)
- Suppose the can initially contains 7x and 5x litres of mixtures A and B respectively
Quantity of A in mixture left
= (7x - 7/12 x 9) litres = (7x - 21/4) litres.
Quantity of B in mixture left
= (5x - 5/12 x 9) litres = (5x - 15/4) litres.
(7x - 21/4) / [(5x - 15/4)+9] = 7/9 = › 28x - 21/20x + 21 = 7/9 =› 252x - 189 = 140x + 147
=› 112x = 336 =’ x = 3.
So, the can contained 21 litres of A. - 10 years agoHelpfull: Yes(4) No(3)
- Total mixer is x.
A=7x/12 B=5x/12
after drawn 9 lit of mixer........
mixer remain(x-9)
So the new ratio of A:B is ...
A=7(x-9)/12 and B=5(x-9)/12
now drawn 9 lit filled with B
so B now contain B=5(x-9)/12 +9...........
now the new ratio of mixer is A:B=7:9
we know the new value of A and B...........put that in this equation
7(x-9)/12:(5(x-9)/12+9)=7:9
=>9x-81=5x-45+108
=>x=36
as known A=7x/12
=>A=7*36/12
=21 - 9 years agoHelpfull: Yes(4) No(2)
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