ANSWER
It took 1 hour 30 minutes
EXPLANATION
It was given that Elena and Jada are 12 miles apart.
This means that the distance between them is

We use the formula,

If Elena covers d miles in

Then Jada will cover,

in

We were told that Elena runs at a constant speed of 5 miles per hour.
This implies that,


and Jadda walks a constant speed of 3 miles per hour.
This implies that,

This implies that,

When Elena and Jada meets,then

We equate the two equations and solve. This implies that,

We cross multiply to get,


This implies that,


The time they met was after