Answer:
40
Step-by-step explanation:
the range is the number between the highest and lowest number. the lowest in this is 5 and the highest is 45
45-5=40
You should be able to multiply 91 by 8 to get the sum of the first 8 tests, then add the score on the 9th test. Then to get the average of the sum of the 9 tests you need to divide it by 9.
((91*8)+78)/9=89.555555555555.... So, 90%
First you'll take 18/2 which equals 9. Then 30/2 which equals 15. Then you can divide both 9 and 15 by 3. So 9/3 equals 3 and 15/3 equals 5. So the answer is 3:5.
