For read, memory references: 168 (0.9(0) + 0.1(1) ) = 16.8
For write, memory refernces : 32 (0.9(1) + 0.1(1) ) = 32
Total memory references, interms of bytes = (16.8 + 32)*128 = 6246.4 ~ 6246
As one line has 128 Bytes
Since write through is used , there is no need to consider dirty bits.