Hi there!
Here we know how much something weighs on the moon in comparison to earth, that is weight on the moon = 0,167 * weight on the earth, because an object on the moon is about 0,167 of its weight on earth. Knowing that, we can calculate the weight of the astronaut on the moon like this:
weight on the moon = 0,167 * weight on the earth
weight on the moon = 0,167 * 156,5
weight on the moon = 26,1355 pounds
The 156,5 pound astronaut weigh 26,3155 pounds on the moon.
Hope this helps!