Answer:
11
Step-by-step explanation:
The mean is calculated as
mean = 
let the third number be x , then
= 15 ( multiply both sides by 3 to clear the fraction )
34 + x = 45 ( subtract 34 from both sides )
x = 11 ← third number
44.4 miles per hour. You just divide 300 and 6.75 (Think as the 3/4 as quarters each 1 is .25) then you will get 44.4. To check your answer you would multiply 44.4 and 6.75 and get 299.7. This is not 300 but when you round that .7 to the nearest 10 you will get 300. Hope this helped.<span />
Answer: 829 3/4 or 829 75/100
Step-by-step explanation: