Two people of 55 kg and 80 kg stand 0.80 m apart…

Step 1. $F = 6.67 \times 10^{-11}\ \text{N m}^2/\text{kg}^2 \times \dfrac{55\ \text{kg} \times 80\ \text{kg}}{(0.80\ \text{m})^2} = 4.59 \times 10^{-7}\ \text{N}$.

Step 2. Weight: $80\ \text{kg} \times 9.8\ \text{m/s}^2 = 784\ \text{N}$, so the ratio is $\dfrac{4.59 \times 10^{-7}\ \text{N}}{784\ \text{N}} = 5.85 \times 10^{-10}$.