Question

Six liters of a 20% solution of alcohol in water are mixed with four liters of 60% solution of alcohol in water the alcoholic strength of the mixture is
a) 34%
b) 39%
c) 38%
d) 36%

Answer 1

6×20÷100=1.2 4×60÷100=2.4 adding both 2.4+1.2=3.6 conc.=3.6×100÷10=36%

Answer 2

first take the first one
6x20/100=1.2
now take the second one
4x60/100=2.4
add both
it will give u
1.2+2.4=3.6
therefore it is option d) 36%