The mass of a jar is 750 g when it is 1/2 filled with orange juice. The sand jar has a mass of 625 g when it is 1/4 filled with oranges.

Question

(a) What is the mass of the jar when it is 3/4 filled with orange juice?
(b) What is the mass of the jar when it is empty?

Answer 1

I assume you mean orange juice in both cases.
Then if the empty jar's mass is m, and the juice's mass when its full is j, then we have
m + 1/2 j = 750
m + 1/4 j = 625
m = 500 g
m + 3/4 j = 750+625-500 = 825 g

Answer 2

I have 1125 g as the first answer - is 825 g for the first question or the second one?