The stock of Company A gained 6% today to $126.14. What was the
opening price of the stock in the beginning of the day?

$118.57

Step-by-step explanation:

6% of $126.14 equals 7.568

$126.14 minus $7.568 equals $118.57

Step-by-step explanation:

Given

Solving (a1): The common difference (d)

d is calculated as

This gives:

Factorize:

Solving (a2): Sum of n terms

This is calculated using:

Substitute values for T1 and d

Factorize:

Solving (b): Sum of first 10.

In this case, n = 10

So:

becomes