Find the missing puppy weight from the mean of a set of five

Q: How do you find the missing puppy weight from the average?

Multiply the average by the number of puppies to get the total weight, then subtract the four known weights to find the missing one.

Q: What is the missing weight here?

The total is 75 ounces, the known weights add to 60 ounces, so the missing puppy weighs 15 ounces.

Question

1. A litter of 5 golden retriever puppies has an average weight of 15 ounces. If four of the puppies weight 12, 18, 19, and 11 ounces, how many ounces does the 5$^{\mathrm{th}}$ puppy weigh?

Acemy AI · Accepted Answer

**Key takeaway**: Average problems like this are really just total-sum problems in disguise. Once you turn the mean into a total, the missing value falls out in one subtraction.

The average weight of 5 puppies is 15 ounces, so the total weight is

$$
5\times 15=75\text{ ounces}.
$$

Add the four known weights:

$$
12+18+19+11=60.
$$

Now subtract:

$$
75-60=15.
$$

So the 5th puppy weighs

$$
\boxed{15\text{ ounces}}.
$$

A quick check: five numbers with total 75 do indeed average to 15.

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**Pitfalls the pros know** 👇
Don’t average the four known puppies and then try to guess the fifth from that. The mean is based on all five puppies together, so you need the total first.

**What if the problem changes?**
If the average had been 16 ounces instead of 15, the total would be $5\cdot 16=80$, and the missing puppy would weigh $80-60=20$ ounces. The method stays the same no matter what the average is.

`Tags`: mean, total, missing value

Question

Find the missing puppy weight from the mean of a set of five

Expert Verified Solution

FAQ

How do you find the missing puppy weight from the average?

What is the missing weight here?