When David's car was repaired,the charge of total labour was $200.This was 4/7 of the total bill.What was the total bill?
$$\frac{4}{7}*bill=200\\\\ bill=200*\frac{7}{4}$$
$${\mathtt{bill}} = {\frac{{\mathtt{200}}{\mathtt{\,\times\,}}{\mathtt{7}}}{{\mathtt{4}}}} \Rightarrow {\mathtt{bill}} = {\mathtt{350}}$$
bill = $350
