5
1) Gathering the data
20 liters of jam has been jarred
+ 1 liter per day
2) We can write an equation for that, since 20liters have already been jarred and 1 liter per day
F(d) = 20 +d F, for filling and d, for days
Since he wants to jar 25 liters, then we can write:
25 = 20 +d Subtract 20 from both sides
25-20= d
d= 5
3) So Vincent will spend 5 more days to fill 25 liters.