Kyla can plant 300 trees in 1 hour
Mia can plant a single tree in about 13 seconds
if they work together how long would it take them to plant 100 trees

We have to find out the number of trees planted per unit rate of time.

Kyla can plant 300 trees in 1 hour, so she can plant 300 trees in 3600 seconds. This implies that she can plant

trees per second.

On the other hand, Mia can plant 1 tree in 13 seconds, so she can plant

trees per second.

Working together they can plant

trees per second, i.e. it takes them 156/25 seconds to plant a tree.

We conclude that they plany 100 trees in

seconds

the answer to your question is b.