Question

A container contains a large unspecified number of​ ping-pong balls. A student takes 80 balls from the​ container, marks them with a blue​ dot, returns the marked balls to the​ container, and thoroughly mixes the balls. She then takes 80 balls again from the container. Of​ these, 16 have blue dots. She now wants to use this data to estimate the total number of​ ping-pong balls in the container. What is an estimate for the number of​ ping-pong balls in the​ container?

Answer 1

400 ping pong balls

Explanation:

Let the total number of ping pong balls =x

Out of x ping pong balls, 80 are marked with a blue dot

Out of 80 ping pong balls, 16 are marked with a blue dot.

Expressing it as a ratio:

x:80=80:16

`(x)/(80)=(80)/(16)\\ 16x=80X80\\x=6400 / 16\\x=400`

There are an estimate of 400 ping pong balls in the container.