Kareem wants to find the number of hours the average sixth-grader at his school practices an instrument each week. Which is the
best way Kareem can get a representative sample? He can randomly survey 50 boys in the school.
He can survey 30 students in the school band.
He can randomly survey 50 sixth-graders in the school.
He can survey 20 friends from his neighborhood.
He can randomly survey 50 sixth-graders in the school. Because if he asked 30 people in the band some people might be in a different grade, if he randomly 50 boys in the school then what if half didn't even play anything. If he did friend what if most friends don't even play a instrument.
Then which one would it be it would be more easier if he did 50 random sixth-graders because they might know friends or themselves and a person who plays an instrument.
To solve this problem you will want to work backwards. Start with the junk mail. There is 18 junk mail and if there are 1/3 as many bills as junk mail then you will need to multiply 18 * 1/3. This equals 6 bills. If there is twice as many bills as letters then you will need to divide bills(6) by 2 which equals 3. If there are 6 more magazines than letters then you need to add 6 to the letters (3). 3 + 6 = 9