Answer: She needs approximately 142.5 pounds
Step-by-step explanation:
From the information given,
A pound of fertilizer covers 39 square feet of lawn.
If the lawn measures 5557.4 square feet, then
the number of pounds of fertilizer that she needs to buy = 5557.4/39 = 142.4975
Rounding to the nearest tenth,
She needs approximately 142.5 pounds