We have been given that Tyrell ate twice as many grape as Katy. Lucy ate half as many grapes as Katy. Katy ate 6 grapes. We are asked to find the total number of grapes that all of them eat in all.
First of all, we will find twice of 6 grapes to find number of grapes eaten by Tyrell.
Now, we will find half of 6 to find number of grapes eaten by Lucy.
Therefore, the three of them eat 21 grapes in all.