Thank you for your question!
I think the conversion that they are after here in order to do the comparison is using the equation T = 10Z + 50
So in this case the T score of 65 translates into a Z score of 1.5
65 = 10Z + 50
15 = 10Z
1.5 = Z
Since that matches Sue’s score of 1.5 that means that they would be equally strong
I hope that helps :)