Let s be the number of times the small bell rings, and b be the number of times the big bell rings. We know that s + b = 52 and s = 4 + 1/3b.
Substituting the second equation into the first equation, we get 4 + 1/3b + b = 52
Subtracting 4 from both sides, we get 1/3b + b = 48
Combining like terms, we get 4/3b = 48
Dividing both sides of the equation by 4/3, we get b = 36
#### 36