Answer:
A. 
Step-by-step explanation:
We are given the expression, 
On re-writing the expression after borrowing 1, we have,
=
i.e.
= 
i.e.
= 
Thus, the equivalent expression after borrowing 1 from the given expression is
.
Hence, option A is correct.
Answer:
1000 / 10 = 100 strikes per second. Now, multiply by 12 to find the number of strikes that occurred. 100 * 12 = 1200 strikes in 12 seconds. Part B: Divide the number of seconds to the number of lightning strikes to find the average rate. 10 / 1000 = 0.1 seconds per strike. Now, multiply by 7250 to find the number of seconds that passed.
Step-by-step explanation:
The scientific notation for 5390000000000 = 5.39 x 10^12