Question

gol. (4) guantity of milk in the last ( =aleft(1-frac{b}{a}right)^{n} ) Here, ( a=81 ) and ( b=27 )
( Rightarrow 81left(1-frac{27}{81}right)^{2} )
( Rightarrow 81left(1-frac{1}{3}right)^{2}=81 times frac{2}{3} times frac{2}{3}=36 )
guantity of water in the last ( =81-36=45 )
( therefore ) Required ratio ( =frac{36}{45}=frac{4}{5}=4: 5 )

# Ex.3. There is 81 litres milk in a container. One third of milk is replaced by water in the container. Again one-third of mixture is extracted and equal te amount of water is added. What is the ratio of milk to water in the new mixture ? (1) 1:2 (2) 1:1 (3) 2:1 (4) 4:5 SSC CGL (Tier-II) 2015

Solution