Final answer:
Holly will use 30 pounds of fertilizer on her back lawn.
Step-by-step explanation:
To find out how much fertilizer Holly will use on her back lawn, we need to subtract the amount she plans to use on her front lawn from the total amount of fertilizer she has.
If Holly has 45 pounds of fertilizer and plans to use ⅓ of it on her front lawn, she will use ⅔ of it on her back lawn.
To calculate this, we can multiply 45 by ⅔:
45 pounds × ⅔ = 30 pounds
Therefore, Holly will use 30 pounds of fertilizer on her back lawn.
\