Answer:
Mr Scruggs received $900 for his birthday.
Explanation:
1. Let´s name x the money Mr Scruggs received for his birthday:
x = money received by Mr Scruggs
2. He spent
of x on dog treats, that is:
spent on dog treats. (Eq.1)
3. He divided the remainder between his 3 favorite charities, that is:
for each carity. (Eq.2)
4. If he donated $60 to each charity, we have to replace this value on Eq.2:

Solving for x:

x = $900
There fore Mr Scruggs received $900 for his birthday.