Answer:
Jill bought 16 books and Sam bought 9 books
Step-by-step explanation:
Let the number of books that Jill bought be j.
Let the number of books that Sam bought be s.
Jill bought 7 more books than Sam:
j = 7 + s
They bought 25 books altogether:
j + s = 25
Put j = 7 + s into the second equation:
7 + s + s = 25
7 + 2s = 25
2s = 25 - 7 = 18
s = 18/2 = 9 books
Therefore:
j = 7 + s = 7 + 9
s = 16 books
Jill bought 16 books and Sam bought 9 books.
