Hi, kindly help with the following working solution.

8) At a party, a group of 9 boys drank an average of 2 glasses of oranges juice. When 4 more girls joined the group , the group now drank an average of 4 glasses of orange juice.

(a) What is the total amount of glasses of orange juice that all the children drank?

(b) What is the average number of glasses of orange juice that the 4 girls drank?

9) The sum of Krishna's salary and Joe's salary was 180% of Vivian's salary. Krishna's salary was 4/5 of Joe's salary. If Vivian's salary was $1800, find the average salary of Krishna and Vivian.

10) The average of 4 numbers is 32. The 1st number is thrice that of the 2nd number. The 3rd and 4th number has the same value. If the average of the 1st and 2nd number is 12, find the sum of the 2nd and the 4th number.

Thanks in advance

Jessica