Answer: Jenna sold 280 and Becca sold 105 boxes.
Step-by-step explanation:
Let 3x be the number of cookies Becca sold.
Then, the number of cookies Jenna sold = 8x
Since Combined, they sold a total of 385 boxes of cookies.
So, [tex]3x+8x=385[/tex]
[tex]\Rightarrow\ 11x=385\\\\\Rightarrow\ x=\dfrac{385}{11}\\\\\Rightarrow\ x=35[/tex]
So, Jenna sold 8(35) = 280 boxes
and Becca sold 3(35)= 105 boxes
Hence, Jenna sold 280 and Becca sold 105 boxes.