Answer:
<em>Grades to be scored in 3rd exam = 88</em>
Step-by-step explanation:
Given that average of 3 numbers is 85.
First two numbers are 81 and 86.
To find:
3rd number so that average is 85
Solution:
Let the third number = 
Formula for average is:

Here, sum of numbers = 
Total count of numbers = 3

<em>Grades to be scored in 3rd exam = 88</em>
Answer:
y is going back by 3's x is going back one
Step-by-step explanation:
It appears that the Pythagorean theorem can be applied to this problem
(distance to shadow)² = (height of building)² + (length of shadow)²
(38 m)² = (height of building)² + (28 m)²
660 m² = (height of building)²
Then the height of the building is
height of building = √660 m ≈ 25.7 m
I believe it would be the 3rd one.