Help please and show me the steps on how u got the answers

6a If 17.5% of the students were 7, then 100% would be 100/17.5 times 7 which equals 40.
Therefore, there are 40 students in total.

6b. The amount of students present would be the amount absent taken away from the amount of the students in the class, which is. 40 - 7 = 33. So 33 students were present.

7. If the hat cost $18 dollars in the 10% sale, the percentage is now 90% of the original price (100-10=90). Therefore, if $18 equals 90%, then 100% (the original price) would be 100/90 times 18 which equals 20. So the original price is $20.

8. Apply the same principle as question 7. 76kg is 95% so his original weight is 100/95 times 76 which equals 80kg. Therefore his weight before the decrease is 80kg.

9. Apply the same principle as question 7 and 8. 185l is 88% so the amount of water before evaporating would be 100/88 times 185 which equals 210.22l. Therefore 210.22l would be left.

Hope this helps and let me know if I made a mistake! :)