Question

I know twice as many jokes as my friend does.

Together we know $60$ different jokes.

There are $3$ jokes that both of us know.

How many jokes do I know $?$

How many jokes does my friend knows $?$

Answer 1

Find the number of jokes me and my friend know:

Let I know $x$ jokes.

Then, my friend knows $2x$ jokes.

Together we know $60$ different jokes.

However we both know the same $3$ jokes:

Therefore, the sum total of jokes will be:

$60+3=63$

So, find the number of jokes known:

$\begin{array}{rcl}x+2x& =& 63\\ & \Rightarrow & 3x=63\\ \therefore x& =& 21\end{array}$

Thus, the number of jokes I know is $21$.

Then, the number of jokes my friend knows:

$$\begin{gathered} 2x=2\times 21 \\ =42 \end{gathered}$$

Hence, I know $\mathbf{21}$jokes and my friend knows $\mathbf{42}$ jokes.