Ratios & Proportion
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Q.

In a mixture 60 litres, the ratio of milk and water $2:1$. If the this ratio is to be $1:2$, then the quantity of water to be further added is:

 A.

20 litres

 B.

30 litres

 C.

40 litres

 D.

60 litres

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Solution:
Option(D) is correct

Quantity of milk = \(60\times \dfrac{2}{3}=40\text{ litres}\)

Quantity of water in it =$(60−40)$ litres =$20$ litres.

New ratio =1:2

Let, the quantity of water to be added further be $x$ litres.

Then milk : water = \(\dfrac{40}{20+x}\)

Now,

 \(\begin{align*} \dfrac{40}{20+x}&=\dfrac{1}{2}\\ 20+x&=80\\ \Rightarrow x&=60 \end{align*}\)

Edit: For an alternative solution, check comment by Sravan Reddy.


(2) Comment(s)


Purnima Bamola
 ()

Initially m:w=2:1 in 60 l

so, m=40 l and w=20 l

finally m:w=1:2

milk will be same in both ratios

so, 1=40 milk

2=80 water

left water=80-20=60 l

so, 60 l water should be added



Sravan Reddy
 ()

Without writing equations:

Initially its 2:1 of 60 litres.

So, 40 litres and 20 litres

Now for 1:2 ratio. Water should be $40*2=80$ litres.

So, 60 litres should be added