Assume the average child weighs 40 pounds at age 3. Assume the average child weighs 70 pounds at age 6. What is the average number of
pounds the child gains per year between ages 3 and 6?

10 pounds per year

The given unit rate is 30 pounds every 3 years.

Now, we will divide 30 pounds by 3 years.

30 pounds ÷ 3 years = 10 pounds per year

The answer is 10 pounds per year.

or

step-by-step explanation:

we need to solve for 'x' the following equation:  

we have that:

⇒

⇒ ⇒

factorizing, we get that:

  ⇒

then, the solutions are: or

nothing extraneous has been found!

3

step-by-step explanation: