Answer:
1.40 litres; order of operations
Step-by-step explanation:
Part A:
First, write it out in the full form.
#1 (.75 litres of blackberry juice + .60 litres of blueberry juice + .25 litres of guava juice) - .20 litres drank = 1.4 litres of juice remaining in the jar
Part B:
Removing the wordy descriptions from the expression, we get the following:
#2 (.75 + .60 +.25) - .20
or, by adding the numbers in the parentheses first:
#3 (1.60) - .20 = 1.40
#4 1.40 litres of juice left in the jar
The order of operations was used in moving from step #2 to step #3, as operations within the parentheses were conducted before subtracting the .20 litres of juice which were drank.