split - problem solving and reasoning

[anikadesilva]

A box contains 20 counter. some are blue and some are white. A counter is taken at random from the box and a colour is noted. The counter is then replaced. This is repeated 240 times
A white counter is chosen 84 times.
How many of each colour do you think are in the box.

Please help with answer

 

[soroban]

Re: problem solving and reasoning

Hello, anikadesilva!

A box contains 20 counter, some are blue and some are white.
A counter is taken at random from the box and a colour is noted; the counter is then replaced.
This is repeated 240 times

A white counter is chosen 84 times.

How many of each colour do you think are in the box?

\(\displaystyle \text{Let }B = \text{number of blue counters.}\)

\(\displaystyle \text{In 240 draws, 84 white counters are drawn.}\)

\(\displaystyle \text{I would assume that: }\;\frac{B}{20} \;\approx\;\frac{84}{240} \quad\Rightarrow\quad B \:=\:7\)


\(\displaystyle \text{Therefore, the box }probably\text{ contains:\;\;7 blue counters and 13 white counters.}\)