Answer:
The mean of the combined group is 76.67 ≈ 77
Step-by-step explanation:
- The sum of the grades in Tom's group is 20×70 = 1400
- The sum of grades in Alice's group is 10×90=900
- The sum of gradees in the combined group is =1400+900=2300
- Then the mean grade of the combined group is

where
- 2300 is the sum of the all grades in the combined group
- 30 is the total number of people in the group
Terms: -4j, -2, -5j, 6
Like Terms: -4j and -5j, -2 and 6
Coefficients: -4, -5
Constants: -2, 6
24 * 5 = 120
120 + 6 = 126 - total cost - meals and service
6/126 *100% = 4,76%
service charge was 4,76% of total costs.
The answer is (((((A ))))))