A laundry manager dilutes $200\text{ ml}$ of liquid detergent concentrate to prepare $1\text{ litre}$ of…
A laundry manager dilutes $200\text{ ml}$ of liquid detergent concentrate to prepare $1\text{ litre}$ of washing solution. How many millilitres of detergent concentrate will he need to prepare $3.5\text{ litres}$ of the same working solution?
$500\text{ ml}$
$600\text{ ml}$
$700\text{ ml}$
$850\text{ ml}$
Solution
Every $1\text{ litre}$ ($1000\text{ ml}$) of solution requires $200\text{ ml}$ of concentrate. For $3.5\text{ litres}$, he requires $3.5 \times 200\text{ ml} = 700\text{ ml}$ of concentrate.