Respuesta :

Write a proportion like so:

4 gallons/30 plants= x gallons/45 plants

Cross multiply to find the value of x
4*45= 180
180/30= 6=x

Final answer: 6 gallons
It will take 6 gallons of water.

4÷2=2
30÷2=15
(every 15 plants you'll use 2 gallons)
15•3=45
2•3=6 gallons