At the ends of the lever are suspended two weights weighing 50 grams and 150 grams. Lever length 1 m. What are the lever arms?

The bodies are most likely in balance. Then we use the statics condition:
M1-M2 = 0
M1 = M2
Where
M1 = F gravity1 * d1
M1 = F gravity2 * d2
F gravity1 = m1 * g
F gravity2 = m2 * g
Means
m1 * g * d1 = m2 * g * d2
Reduce g:
1) m1 * d1 = m2 * d2.
We know that shoulders add up to 1.
d1 + d2 = 1
Or
2) d1 = 1-d2
Let’s substitute 2 in 1:
m1 * (1-d2) = m2 * d2
m1-m1 * d2 = m2 * d2
Substitute m1 and m2
50-50 * d2 = 150 * d2
50 = 200 * d2
d2 = 50/200 = 1/4 = 0.25 m
d1 = 1-d2 = 1-0.25 = 0.75 m