After 1 hour >> 44 miles apart
after 2 hours >> 88 miles apart
after 2.5 hours >> 110 miles apart
Two and a half hours
Let X denote <span>the baby’s weight.
Let y represent </span>the doctor’s weight.
Let z stand for the nurse’s weight.
From the equations: x + y = 78 implies y = 78 - x
and x + z = 69 gives z = 69 - x
then we have x + y + z = 142
Substituting y = 78 - x and z = 69 - x into the equation x + y + z = 142
x + y + z = 142
x + 78 - x + 69 - x = 142
-x + 147 = 142
-x = -5
x = 5
Conclusion
<span>the baby’s weight was 5 kg</span>