If Statement (PHP)

I need If Statement (php) to :

• if (Modem = ModemNotReceived) and (CheckModem = Done)

  Total + 50

And

• if (Modem = ModemReceived) and (CheckModem = Done)

  Total - 50

How i can do that in one if statement

My Table :

| ID |       Modem          | CheckModem | Total
------------------------------------------------
| 1  |   ModemReceived      |    Done    | 120
------------------------------------------------
| 2  |   ModemNotReceived   |    Null    | 90
------------------------------------------------
| 3  |   ModemReceived      |    Null    | 100