Scott jarred 10 liters of jam after 5 days. how many days does scott need to spend making jam if he wants to jar 16 liters of jam in all? assume the relationship is directly proportiona

The proportion can be written

... days/(16 L) = (5)/(10 L)

Multiplying by 16 L gives

... days = (16 L)×5/(10 L) = 8

It will take Scott 8 days to jar 16 L of jam.

Or, you can consider that Scott jars 2 L per day. (= (10 L)/(5 days)). At that rate, it will take him (16 L)/(2 L/day) = 8 days. This is the same as the above proportion written "upside down":

... (16 L)/(days) = (10 L)/(5 days)

Multiplying by the denominator on the left, and dividing by the ratio on the right, this becomes ...

... (16 L)/((10 L)/(5 days)) = days = (16 L)/(2 L/day) . . . . . . as above

You can solve the proportion from any of the 4 ways it can be written, but it can be easier to solve if the unknown is in a numerator. Another way to write it with the unknown in the numerator is ...

... days/5 = (16 L)/(10 L)

... days = 5×1.6 = 8 . . . . . . multiplying by 5