Let us say that:
x = weight of llamas
y = weight of okapi
From the problem, we can create the equations:
x + y = 450 --> 1
3 x = y + 190 --> 2
Rewriting equation 1:
x = 450 – y
From equation 2:
3 (450 – y) = y + 190
1350 – 3 y = y + 190
4 y = 1160
y = 290
From equation 1:
x = 450 – 290
x = 160
Therefore a llama weighs 160 kilograms while okapi weigh 290 kilograms on average.