Afactory can make 3×10^4 t-shirts per day, how many t-shirts will it make in 2.5 × 10^2 days?

3 x 10^4 = 30000
2.5 x 10^2 = 250

30000 * 250 = 7 500 000 t-shirts

Another way showing the answer

3 x 10^4 * 2.5 x 10^2 = 7.5 x 10^6
As you multiple 3 by 2.5 and add 4 and 2 for the degree

Then just do it (lol)