Step-by-step explanation:
(example)
Think of it this way:
If joe caught 1 fish only
and bonita caught four more than joe
that means that she caught 5 fish in total.
(for the question)
This means that Bonita caught four more fish than Joe.
j + 4 = bonita
j = joe
The correct answer is B = -1
10(1 + 3B) = -20
10 + 30B = -20
-20 - 10 = -30
30B = -30
B = -1
Hope this helps :)