PLEASE HELP THE FIRST ONE TO GET IT RIGHT AND GIVE ME A EXPLAINTION ON HOW YOU GOT IT GETS A brainiest!!!

Two customers went to a post office. first customer paid $12 for 14 and 5 envelopes the second paid 24.80 for 10 postcards and 15 envelopes. what is cost of each envelope?

Asurvey of 2,000 doctors showed that an average of 3 out of 5 doctors use brand x aspirin.how many doctors use brand x aspirin

Select the correct answer. employee earnings per month($) 1 1,200 2 2,600 3 1,800 4 1,450 5 3,500 6 2,800 7 12,500 8 3,200 which measure of spread is best for the data in the table? a. range b. quartiles c. interquartile range d. mean absolute deviation