Answer
1.9×〖10〗^(-4)
Explanation
A number is said to written in scientific notation when it is in the form A×〖10〗^n, where 1≤A<10 and n is an integer.
In this case,
19 hundred thousandths =19/100,000=0.00019
0.00019=1.9×〖10〗^(-4)
19 hundred thousandths to scientific notation = 1.9×〖10〗^(-4)