Question A:
If you take 90 and 3 and divide them, you will get 30. This means that there are 30 rows on the right side of the plane.
Now all you have to do is simply multiply 30 and 2 to get the number of seats on the left side...
30 * 2 = 60
Answer: There are 60 seats on the left side of the plane
Question B:
To find the amount of seats all together, simply add 90 and 60...
90 + 60 = 150
Answer: 150 seats
