Compute each product or quotient. Write the final answer in scientific notation.

1. $(6\times10^2)(4\times10^5)$ 

   Hint 1 (a):

   What is $6 \cdot 4$?
   What is $10^2 \cdot 10^5$?

   Hint 2 (a):

   $24 \cdot 10^7$
   Is this in scientific notation?

2. $(1.75\times10^{−2})(8\times10^{−8})$ 

   Hint (b):

   See part (a).

3. $\frac { 9 \times 10 ^ { 5 } } { 4 \times 10 ^ { 7 } }$ 

   Hint 1 (c):

   $\text{What is }\frac{9}{4}?$

   $\text{What is }\frac{10^{5}}{10^{7}}?$

   Hint 2 (c):

   $2.25 \cdot 10^{−2}$