Add and subtract the values. Express your answer in scientific notation.
(6.15 times 10 Superscript 8 Baseline) minus (2.5 times 10 Superscript 7 Baseline) + (3.4 times 10 Superscript 9 Baseline)
6.24 times 10 Superscript 8
7.05 times 10 Superscript 8
3.99 times 10 Superscript 9
4.04 times 10 Superscript 9