Mixtures and Alligation

In what ratio must a grocer mix teas at Rs. $60$ kg and Rs. $65$ kg, so that by selling the mixture at Rs. $68.20$ kg, he may gain 10%

A mixture of water and milk is $40$ litres. There is $10$% water in it. How much water should now be added in this mixture so that the new mixture contains $20$% water?

$37.85\%$ and $92\%$ alcoholic solutions are mixed to get $35$ liters of an $89\%$ alcoholic solution. How many liters of each solution are there in the new mixture?

140 litres of an acid contains 90% of acid and rest water.The amount of water added to make the water 12.5% of the resulting mixture is

A $15$ liter of a mixture contains $20$% alcohol and rest water. if $3 $ liter of water is added in it, find the % of alcohol in the new mixture.

A man purchased certain no. of toffees at $25$. a rupee and same no. at $20$. a rupee. he mixed them together and sells them at $45$ per $2$ toffees. What does he gain or loss in this transaction.

The cost of pure milk is Rs. 16 per liter. On adding water, the mixture is sold at Rs. 15 per liter. In this way the milk man earns 25 % profit. What is the ratio of milk and water in the mixture?

The ratio in which tea costing Rs. $192$ per kg is to be mixed with tea costing Rs. $150$ per kg, so that the mixed tea when sold for Rs. $194.40$ per kg, gives a profit of $20 \%$

A sweet water initially contains $500\ gms$ of sugar in $10\ litres$ of water. Water flows in at the rater of $0.5$ lit/ m and the mixture flows out at the same rate therefore of sugar present after $20$ minutes is