Answer: 35 trading cards
Explanation:
Assume the trading cards collected by Trey is x.
That means that the number of trading cards collected by Abigail is 7x.
Relevant expression is:
7x + x = 40
8x = 40
x = 40/8
x = 5 trading cards
This means that Trey collected 5 trading cards
Abigail collected 7 times that figure so Abigail collected:
= 7 * 5
= 35 trading cards