The length of the lever is 2 m. At its ends, weights of 20 tons and 140 tons are balanced. Find the lever arms.

m1 = 20t = 20000kg,
m2 = 140t = 140000kg,
L = 2m;
l1 -? l2 -?
From the Leverage Rule:
F1 * l1 = F2 * l2;
where
F1 = m1 * g – weight of the first cargo,
F2 = m2 * g – the weight of the second load,
g is the acceleration of gravity;
We get:
m1 * l1 = m2 * l2:
l1 / l2 = m2 / m1 = 140,000/20000 = 7;
Leverage Amount
l1 + l2 = L;
l1 = 7 * l2;
8 * l2 = L;
l2 = L / 8 = 0.25m;
l1 = 1.75m.