From first credit card which has a credit limit of $1000, you have utilized $410. It means you have consumed
410/1000 =0.41*100= 41% of first card
From second card which has a limit of $1000, you have consumed $510. It means you have utilized
510/1000= 0.51*100= 51% of second card
Overall utilization can be calculated as following:
(46% + 51% )/2= 46%