x = one bedroom units
y = two bedroom units
z = three bedroom units
We know that:
x = 3 z ---> 1
y + z = x ---> 2
x + y + z = 156 ---> 3
Therefore combining 2 and 3:
2 x + 156
x = 78
from 1:
z = x / 3
z = 78/3
z = 26
from 2:
y = x – z
y = 78 – 26
y = 52
The summary of answers:
one bedroom (x) = 78
two bedroom (y) = 52
three bedroom (z) = 26