Answer:
10kg
Step-by-step explanation:
For UPS;
express fee = $10
If one kg costs $2, then x kg of package will coat $2x
Total cost of shipping xkg of package will be 10+2x
For FedEx;
Fixed express fee = $20
If one kg costs $1, then x kg of package will coat $1x
Total cost of shipping x kg of package is 20+x
If the total costs of the two options are the same, then;
10+2x = 20+x
2x-x = 20-10
x = 10.
Hence Eric sent 10kg of package