The solutions we had in, varied in the ways they were expressed.
We had many contributions from Crudgington Primary School in Shropshire, U.K.
First I looked at the information and saw that the bean plant grew only $1$cm after $10$ days! So I started from $10$ days. And after the bean plant grew $1$cm the tomato plant had already grown $38$cm. And then after each day the bean plant doubled its current size and the tomato plant grew $5$cm. So after $15$ days both plants are $63$cm.
From Curl Curl North School in New South Wales we had two answers that at first looked different but were just being expressed from a different point of view. Christopher, Ashton, Grace, Charlotte, Kaden, Ben, Kate, Charlie, Dylan, Josh, Matthew and Mitchell's team, said;$6$ days from the time the bean was first measured.
And from Sean, Emma, Emily, Amelia, Ed and Stacey's team we had:$5$ days because you count from when the bean was $3$ cm tall.
I wonder if they thought the other team had the wrong answer?