Question

. How many millimetres of water should be added to 9 ml of a shaving lotion containing 50% alcohol to make it a lotion containing 30% alcohol ?

Answer 1

9 ml of lotion contains 50% alcohol i.e. half of the lotion is alcohol which is 4.5 ml Now assume x ml of water is added to make it 30% alcohol that is , 4.5/(x+9)=30/100 On solving you get x=6 Hence 6 ml of water is added to reduce it to 30%.

Answer 2

we should follow the similar procedure given already and add 6ml to reduce it to 30%