If Vera's phone has a battery life of 2/5 and it drains 1/9 every hour we can determine how much per hour her battery drains.
f the battery drains 1/9 per hour we know how much it drains per hour. To get the time is takes for 2/5 battery life to drain we can say 2/5 divided by 1/9.
We have 5 and 1 at the bottom of the line and 9 and 2 at the top of the line. We can simplify: