7th grade math problems!!-example: What percent of the states in the U.S. do not border any other states?

Question

1. The maximum speed of a zebra is 40 miles per hour. At this speed, how long would it take the zebra to run one mile?

2. Elvis Presley made 90 more "singles" than "albums" that were major hits. The total number of singles and albums is 250. How many singles hits did Presley make?

3. What percent of the states in the U.S. do not border any other states?

4. How many games are played in a 5 team round-robin tournament?

5. In what year of the 18th century was Washington, D.C. Selected as the United States capital? The year is a multiple of 10. The tens' digit is 2 more than hundreds' digit.




now, those who are going to be plain out dumb and say something like: do your own homework - or somethin like that, you can just go answer some other question if you have such a problem with it. Curious how many people would get this stuff right>

Answer 1

1) 1.5 minutes

2) x + x +90 = 250

2x + 90 = 250

2x = 160

x = 80

80 Albums, 170 Singles

3) 2 states ( i think, im not from the U.S.) 4%

4) 1v2, 1v3, 1v4, 1v5, 2v3, 2v4, 2v5, 3v4, 3v5, 4v5 = 10

5) 1790

Answer 2

1. The maximum speed of a zebra is 40 miles per hour. At this speed, how long would it take the zebra to run one mile?

40 mph = 40 miles per 60 minutes.
So zebraruns 1 mile in 60/40 minutes = 1.5 minutes

2. Elvis Presley made 90 more "singles" than "albums" that were major hits. The total number of singles and albums is 250. How many singles hits did Presley make?

x= # of albums
90 +x = # of singles
90+x+x = 2x+90 =250
2x = 160 so x=80
x+90 = 170 = # of singles

3. What percent of the states in the U.S. do not border any other states?
2 states (Hawaii and Alaska) do not border any other state.
There are 50 states so 2/40 =4/100 =4% do not border another state.

4. How many games are played in a 5 team round-robin tournament?
n/2(n-1) games . For 5 teams this would be 5/2(5-1)= 10


5. In what year of the 18th century was Washington, D.C. Selected as the United States capital? The year is a multiple of 10. The tens' digit is 2 more than hundreds' digit.

This would be in the 1700's so ten's digit must be 9 so answer is 1790.

Answer 3

1. Set up like a proportion. 40 miles/1 hour = 1 mile/x. Cross multiply: 40x = 1; so it would take a zebra 1/40 of an hour to run one mile, or 1.5 minutes.

2. Use a system of equations. s + a = 250 and s = a + 90. Plug in the second equation to the first:
(a + 90) + a = 250
2a = 160
a = 80; s = 170

3. Hawaii and Alaska; so 2/50 or 4%

4. The formula to find how many games in a round-robin tournament is (n/2)(n − 1), or 2.5(4) = 10 games.

5. The 18th century is the 1700's. The first two digits would be 17__. The last digit is 0 because the number is a multiple of 10, and the ten's digit is two more than the hundreds, or 9. The answer is 1790.

Answer 4

Ok I'll bite, since you threw the little challenge at the end..
example : 2 states = 4%
1. 40 mph = 1 mile in 1/40 of an hour or 1.5 min
2. S = 90 + A
S + A = 250
90 + A + A = 250
2A = 160 A = 80 S = 170 80 albumns 170 singles
4, Not sure how round robin tournaments work but I would guess that if you get all pairs out of the 5, eliminate the lowest scorer, then get all pairs out of the 4, eliminate the loser, and so on, till you get down to the last two, that would be C(5,2) + C(4,2) + C(3,2) + C(2,2) = 10 + 6 + 3 + 1 = 20. And if that's how a round robin works, the number of possible outcomes would be the product of all these, 180. Wouldn't swear to this one tho.
5. 18th century means 1700's. Tens digit two more than hundreds digit and the year a multiple of 10 would be 1790.
How'd I do? Do I get to pass to 8th grade?

Answer 5

3. 4% 2/50 (Alaska and Hawaii)