As a clinical chemist in charge of the testing of blood samples. You are required to mix a solution of sodium chloride with water in the ratio of 2:5.

=2:5

2/7 of whole solution chloride

5/7 of whole solution is water

780ml = 2/7

1/7 = 390 ml

5/7 = 1950

Total solution

=2730ml

780ml = sodium chloride

1950ml = water

780:1950ml.

How do I put that in standard form and to an appropriate number of significant figures?