What quantity of 75% acid solution must be mixed with 25% solution to produce 720 ml of a 50% solution

Step-by-step explanation:

and

both volumes combined makes the last solution...

and

now...

0.5x+0.5y=0.75x+0.25y

0.25y=0.25x

x=y

it means both volumes are same

so volume of acid must be 720/2=360mL

plug that number in to x and y

if u didnt get how i got the answer...comment me

distance covered by pamela in 9 l of fuel = 99km

let us apply unitary method here.

distance covered by pamela in 1 l of fuel =99/9 =11 km

now let us find distance covered by pamela if she has 12 l of fuel.

distance covered in 12 l = distance covered in 1 l of fuel * 12

we know that distance covered by here in 1 l is 11 km.

so distance covered in 12 l of fuel = 11*12 = 132 km.

answer: c.  

step-by-step explanation:

mixtures containing substances that get attracted to magnet can be separated using a magnet. we can separate iron from a mixture of sand and iron, as only iron attracts to the magnet.