Using ingredient prepared frui if it measures less

Rhubarb-strawberry-jam

• 1 rhubarb
• 1 pouch liquid pectin
• 1/4 space at top
• 7,600 ml saucepan
• 1,300 gr sugar
• 850 gr prepared frui if it measures less (slightly)
• 600 gr strawberries (fresh)
• 60 ml water