90 < [( n + n + 2 + n + 4) / 2] < 105
90 < (3n + 6) / 2 < 105
3n + 6 > 180 and 3n + 6 < 210
n > 58 , n < 68
58 < n < 68 answer
Answer: The number of calories increased by 20%.
Step-by-step explanation:
Given : The doctor recommended that Mike increase the number of calories he burns working out from 1,500 to 1,800.
Previous number of calories he used to burn = 1,500
Increase in calories = 1800-1500=300
Now , the percent increase in calories = 

Hence , the number of calories increased by 20%.
Because it is a 90° angle and the legs are congruent, the legs intersect with the hypotenuse at the same angle, so the other, unnamed angle at the bottom left is equal to x.
Now we can state that:
2x + 90 = 180
2x = 90
x = 45