Question 763741
Small jar = x
Large jar = y
2x + y = 7.......1
3x + 3y = 15.....2
Multiply (10 by 3
6x + 3y = 21.....3
3x + 3y = 15.....2
Subtract (2) from (3)
3x      = 6
 x      = 2
Substitute x = 2 in (1)
2x + y = 7
2(2) + y = 7
4  +  y = 7
      y = 7 - 4
      y = 3
Small jar contains 2 litres
Large jar contains 3 litres.
Hope this helps.
:-)