Answer
Find out the how much hardener should be added to 19 containers of resin .
To prove
Let us assume that the hardener should be added to 19 containers of resin be x .
As given
The formula for glue says to add 60 ml of hardener to each container of resin.
than the equation become
x = 19 × 60
x = 1140 ml
Therefore the 1140 ml hardener should be added to 19 containers of resin .
Hence proved
