Quantitative Aptitude - Arithmetic Ability Questions

The usual way to find the compound interest is given by the formula A = .p(1+r/100)^n

In this formula,

A is the amount at the end of the period of investment

P is the principal that is invested

r is the rate of interest in % p.a

And n is the number of years for which the principal has been invested.

In this case, it would turn out to be A =1500(1+20/100)^3

= 2592.

         Milk             Water 

         74%             26%        (initially) 

         76%             24%        ( after replacement) 

  Left amount = Initial amount 1-replaced amounttotal amount 

   24  = 261-7k

=> k = 91 

Speed in still water = 6 kmph

Stream speed = 1.2 kmph

Down stream  = 7.2 kmph

Up Stream = 4.8 kmph

x/7.2 + x/4.8 = 1

x = 2.88

Total Distance  = 2.88 x 2 = 5.76 kms

Suppose the vessel initially contains 8 litres of liquid.

Let x litres of this liquid be replaced with water.
Quantity of water in new mixture =  3-3x8+xlitres.

Quantity of syrup in new mixture =  5-5x8 litres.

  3-3x8+x=5-5x8

=>   5x + 24 = 40 - 5x 

=>   10x = 16    => x = 8/5

So, part of the mixture replaced = 85×18 = 1/5.

$$\begin{gathered} 68 x ? - 3421 = 591 \\ ? = 4012/68 \\ ? = 59 x 59 \\ ? = 3481 \end{gathered}$$