So 100% of $1250 is $1250. Taking that into factor, we simply need to double it and then add another 39% to that number. So from doubling we get $2500. To find the 39% cross multiply and divide and you should get $487.50. Add the two number to get an answer of $2987.50
1250×39 = 48750
48750÷100 = 487.5
$2500 + $487.5 = $2987.50