Question

Compound x is made of two parts A and one part B. The mass of compound X is 45, and A has twice the mass of B. Which two equations would you solve to find the individual masses of A and B?

Answer 1

Compound x is made of two parts A and one part B.

Hence, the compound x is 2A+B

Let’s use the individual mass of A is $m_A$ and individual mass of B is $m_B$ .

The mass of compound X is 45

$2m_A + m_B=45 \\ m_A=2m_B \\ m_A -2m_B=0 \\ 2m_A -4m_B =0 \\ 2m_A -2m_A +m_B + 4m_B = 45 \\ m_B = \frac{45}{5} = 9 \\ m_A = 2 \times 9 = 18$