Question

Diego has 7 packs of markers. Each pack has x markers in it. After Lin gives him 9 more markers,he has a total of 30 markers

Answer 1

For this case we must find:
x = the number of marbles in a package.
For this, according to the statement we have the following equation:
7x + 9 = 30
Clearing x we have:
7x = 30-9
x = 21/7
x = 3 marbles
Answer:
Each pack of marbles contains 3 marbles