Let the rate of second quality be Rs x per Kg.

C.P of 1Kg wheat of 1st 980p 

Step 1 : 

S.P of 1 kg of mixture = Rs. 9.24

Gain = 10%

C.P of 1 kg of mixture =[100/100+10×9.24]=Rs.8.40

⇒Mean price = Rs. 8.40

Step 2 : 

C.P of  1 kg of sugar of  1st kind = 900p

C.P of  1 kg of sugar of  2nd kind = 700p

Mean price = 840p

Milk in 1 litre mixture in 1st can = 3/4 litre. 

Milk in 1 litre mixture in 2nd can = 1/2 litre. 

Milk in 1 litre final mixture = 5/8 litre. 

By rule of alligation we have required ratio 5 : 8

Let cost price of milk be Rs 1 per liter, then S.P of mixture is also Rs 1 per liter 

Now CP of mixture be = 1 - ( 20 % of Rs 1 ) = 1 - ( 20 * 1 / 100 ) = 80 / 100 = Rs 4 / 5

Listen ques first we can answer within 10 seconds

Given that,

3 parts of water

5 parts of syrup

Total parts is 8

Ques is mixture may be half water and half syrup

So, 4 parts of water  , 4 parts of syrup need

From 5 parts of syrup 1 part need to drawn and replace by water

So 1/5 part of mixture need to drawn and replace by water

1/5 part of syrup = 1 part

We don’t want to consider about 1/5 part of water , because again those filled by water only know.

Answer 1/5