Ans is A

Let X be the number of orange juice gallons to be added

Orange juice in 1 gallon (40%)= .40 gallons

therefore .40+X/(1+X) = .60

solving this u will get X=.5

krazy800 wrote:Ans is A

therefore .40+X/(1+X) = .60

How u arrived on this eqution

Ok... it is the total concentration of orange juice (.40+X) divided by the total number of gallons after mixing additional gallngs of orange juice which is (1+X)

there for percentage of orange juice can be determined by (.40+X)/(1+X)

by equating it to 60% u will get the value of X which is .5

total 1 gallon

let me take 1 gallon as 100 units [for eay understanding]

so juice = 40
water =60

now after adding juice
we want juice to be 60
and water to be 40

water = 60 (which will be 40% in new mixture)
so total new = 150
juice = 90

already availble juice = 40
added = 50

divide by 100 [to go back to gallons]

ans is .5

0.4+x / 1+x * 100 = 60

x = 1/2