Final answer:
The equation for the weight of the newborn baby in terms of time is w = 5 + 1.25t.
Step-by-step explanation:
To write an equation for the weight of the newborn baby in terms of time, we can use the information given. We know that the baby's weight at birth was 5 pounds and after 4 months it was 10 pounds.
Let's let 't' represent the number of months after birth. At birth, the weight is 5 pounds, so the equation is:
w = 5
After 4 months, the weight is 10 pounds, so we can write another equation:
10 = 5 + k(4)
To find 'k', we need to solve for it:
10 = 5 + 4k
4k = 5
k = 1.25
Therefore, the equation for the weight 'w' of the newborn baby 't' months after birth is:
w = 5 + 1.25t