Part A: 2 ( 17 + 2 )
Part B: 38
Explanation:
Since it's asking for the total length of the hike and it says that he has already hiked 17 km and that he still needs to hike 2 more km, you can assume that you need to add 17 + 2 together in order to find the half of his goal.
It states that 19 km is only half of his goal so in order to find the total amount he wants to travel you need to multiply 19 by 2.
