Question

Maths SB ch1 pg1.18 Q.114
Plz explain in detail step by step. ​

Answer 1

Answer : Opt.( a ) 81 ml

Step by step explanation :

Given :

729 ml of mixture contains milk and water in the ratio 7 : 2.

Thus,

Total milk in 729 ml mixture = [ 7/9 ] × 729

= 7 × 81

= 567 ml

Total water in 729 ml mixture = [7/9] × 729

= 2 × 81

= 162 ml

Now,

Let 'x' ml water be added to the mixture to get the ratio 7 : 3.

So,

$\tt {\frac{567}{162 + x} = \frac{7}{ 3}}$

3 × 567 = 7 ( 162 + x )

1701 = 1134 + 7x

7x = 567

x = 81 ml

81 ml water needs to be added.

Thus,

Opt. ( a ) 81 ml is the answer.

Answer 2

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Opt.( a ) 81 ml

Step by step explanation :

Given :

729 ml of mixture contains milk and water in the ratio 7 : 2.

Thus,

Total milk in 729 ml mixture = [ 7/9 ] × 729

= 7 × 81

= 567 ml

Total water in 729 ml mixture = [7/9] × 729

= 2 × 81

= 162 ml

Now,

Let 'x' ml water be added to the mixture to get the ratio 7 : 3.

So,

567/165+x = 7/3

3 × 567 = 7 ( 162 + x )

1701 = 1134 + 7x

7x = 567

x = 81 ml

81 ml water needs to be added.

Thus,

Opt. ( a ) 81 ml is the answer.