# Math Help - Word problem.. anyone?

1. ## Word problem.. anyone?

Liquid A has 10 grams of element X per liter. Liquid B has 15 milligrams of element Y per cm^3 (there are 1000 milligrams in a gram and 1000 cm^3 in a liter). It is desired to make 130 grams of molecule Z. To make 18 grams of Z requires 2 grams of X and 16 grams of Y. How many liters of each liquid should be used?

2. I will quickly try to tackle this.

We have;

$(1)~~~A~=~10gl^{-1}~of~X$

$(2)~~~B~=~15mgcm^{-3}~of~Y$

$~=~15\cdot10^{-3}gcm^{-3}$

$~=~15gl^{-1}$

$18g~of~Z~=~2g~of~X~+~16g~of~Y$

$\implies~130g~of~Z~=~\frac{130}{9}g~of~X~+~\frac{1 040}{9}g~of~Y$

We want $\frac{130}{9}g~of~X$ hence we need $\frac{130}{90}l$ of $A$
We also want $\frac{1040}{9}g~of~Y$ hence need $\frac{208}{27}l$ of $B$