The biggest confusion out here would regarding that of baud rate or bit rate. Baud rate is supposed be no. of Signal elements per second and still we use for the calculations regarding bits.
One can say that bitrate is not given. But they have mentioned the communication to be of Serial link type, and for any serial link communication ( be it asynchronous or synchronous) the baud rate and data rate are both same i.e. in serial links, one bit is transmitted in one signal.
So, if it says that baud rate is 9600, it must be clear that 9600 signal elements will be transmitted per second, all carrying 1 bit each, making the bit rate as 9600 bits per second.
That being done, since its asynchronous, all bytes will be accompanied with some extra bits.
So, to transmit one byte, we will have to put in 12 bits (8 bits of data + 1 start bit + 1 parity bits + 2 stop bits) and not just 8 bits.
$\frac{9600*15}{(1+8+1+2)}$ Bytes=12000 Bytes.
So, whenever if Serial Link is given, it is assumed that the student has the knowledge that baud rate and bit rate are supposed to be the same.
And also most of the times, as Serial communication is used for short distance purposes, these used in asynchronous only.
For example, those 9 pin male connectors in old computers to connect printers and monitors used this type of commination mode.