Maxium Allowable Current to (+/-) 2% ?

[Melqarthos]

Maxium Allowable Current to (+/-) 2% ?

Homework Statement

An experiment on the Earth's magnetic field is being carried out 7.00 from an electric cable.
What is the maximum allowable current in the cable if the experiment is to be accurate to 2.0 ? Assume that Earth’s magnetic field is .

Homework Equations

B = [I*μ]/[2*Pi*d]

The Attempt at a Solution

Check the picture to see how far I've gotten, but it's still wrong. I'm not sure how to attempt this problem.

 

[Melqarthos]

So any suggestions mates?

Melqarthos

 

[ttx1500t]

you have to use 1750 * 2.0%

1750 * 0.02 = 35 A