The first evening she received x calls.
The second evening she received 7 fewer calls than the first evening, so she received x-7 calls.
The third evening she received 3 times as many calls as the first evening, so she received 3x calls.
Over the three evenings she received 73 calls altogether.
The first evening she received 16 calls, the second evening she received 9 calls, the third evening she received 48 calls.
The second evening she received 7 fewer calls than the first evening, so she received x-7 calls.
The third evening she received 3 times as many calls as the first evening, so she received 3x calls.
Over the three evenings she received 73 calls altogether.
The first evening she received 16 calls, the second evening she received 9 calls, the third evening she received 48 calls.