Same attribution depending on salary

Question

there's a house hold that consists of a husband and a wife, the husband earns $1500$ and the wife earns $2000$ and their rent is $2000$, what's the calculation to determine what percentage of their salary should be given depending on what they earn; Example: since the wife earns $2000$ she should pay $60$ or $70$ percent of the rent and the husband $30$ or $40$ since he earns less, how can I calculate that according to their salary? Thanks!!

Answer 1

If the husband makes $h$ and the wife makes $w$, the husband's percentage should be

$$\frac{h}{h + w} \times 100\%$$

Likewise, the wife's should be

$$\frac{w}{h + w} \times 100\%$$

As a particular case, if the husband makes $\$1500$ and the wife makes $\$2000$, then the husband's share is

$$\frac{1500}{3500} \times 100 \% \approx 43 \%$$