Final answer:
The total change in the value of Ishmael's stock is $4.
Step-by-step explanation:
The total change in the value of Ishmael's stock is calculated by adding the increase on Thursday with the decrease on Friday.
On Thursday, the stock went up $17.
On Friday, the stock went down $13.
To find the total change, we add the increase and the decrease:
$17 + (-$13) = $4
Therefore, the total change in the value of Ishmael's stock is $4.