Twice their Friday's earnings is $147 x 2 = $<<147*2=294>>294.
So, their Saturday earnings was $294 + $7 = $<<294+7=301>>301.
Their Sunday earnings was $147 + $78 = $<<147+78=225>>225.
Therefore, their total earnings in three days was $147 + $301 + $225 = $<<147+301+225=673>>673.
#### 673