Can someone me with this on the number 8 question

What are the constants in this expression? -10.6+9/10+2/5m-2.4n+3m

Select the margin of error that corresponds to the sample mean that corresponds to each population: a population mean of 25, a standard deviation of 2.5, and margin of error of 5%

At the county fair, the baxter family bought 6 hot dogs and 4 juice drinks for $12.90. the farley family bought 3 hot dogs and 4 juice drinks for $8.55. find the price of a hot dog and the price of a juice drink.