We have the next number

The expanded form of the number is

Also, we can verify that Alex was incorrect because if we do the sum of the expanded form that Alex calculated we obtain

Finally, the correct answer is
Answer:
C) (9,15)
Step-by-step explanation:
1) For each dot you go right 3 up 5 to get to the next dot.
2) right 3 up 5 from (6, 10) would be (9,15)
It is 6 as one of them is +3 and the other is -3, the difference between 3 and -3 is 6
Answer:
Total distance = 3 1/6 km = 19/6 km
Total time = 1/4 hr
Avg. speed = 19/6 x 4 = 76/6 = 38/3
= 12.67 km/hr