If Ernie's income is 4/5 of what it used to be, she is earning 4/5*$6000=$<<4/5*6000=4800>>4800 now
Jack's income is now twice what Ernie used to make a total of 2*$6000 = $<<2*6000=12000>>12000
Combined, Ernie and Jack are making $12000+$4800 = $<<12000+4800=16800>>16800
#### 16800