Every evening jenna empties out her pockets and puts her change in a jar. at the end of the week she counts her money. one week she had 40 coins, all of them dimes and quaters. when she added them up she had a total of &7.75.
how many dimes did jenna have??

Question

Every evening jenna empties out her pockets and puts her change in a jar. at the end of the week she counts her money. one week she had 40 coins, all of them dimes and quaters. when she added them up she had a total of &7.75.
 how many dimes did jenna have??

anonymous · Answer

You can use the following system equations where:
The number of dimes is $d$, and the number of quarters is $q$:$$\begin{array}{}
&d&+&&q &=& 40\
$0.10&d&+&$0.25&q &=&$7.75
\end{array}$$