Math reassurance?

Okay i have to take math online for now. . .and every once in a while i come across a problem that i cant make up my mind on.





I DO HAVE ANSWERS!! I just need help making sure they are correct.





These math tests make up a very large proportion of my grade so i have to do well.





1)The sum of three consecutive integers is 0. Which equation can be used to determine the integers?





a)3n - 3 = 0


b)3n + 3 = 0


c)-3n + 3 = 0





2)Solve for a. 3 = 7





a)a = 6


b)a = 13


c)a = 20





3)Given: A = h(a + b). Solve for A, if h = 6, a = 5 and b = 7





a)a = 18


b)a = 36


c)A = 72





4)An engine makes 300 revolutions per minute. Which proportion represents the number of revolutions it will make in 15 minutes?





a)x/300 = 15


b)300/x = 15


c)x/300 = 1/15








5)Ann's age is one-fifth the age of her aunt. If Ann is 14 years old, how old is her aunt?





a)50 years old


b)60 years old


c)70 years old








Please help?

Math reassurance?
1. B





First, try solving each of the equations:





a) 3n - 3 = 0


3n = 3


n = 1 -----%26gt; 3 consecutive integers: 1+2,+3 ≠ 0


b) 3n + 3 = 0


3n = -3


n = -1 -----%26gt; 3 consecutive integers: -1+0+1 = 0


c) -3n + 3 = 0


-3n = -3


n = 1 -----%26gt; 3 consecutive integers: 1+2,+3 ≠ 0





2. C





I think you meant to write (a/2) – 3 = 7





First, add 3 to both sides:





(a/2) – 3 = 7


(a/2) = 10





Now multiply by 2 to clear the denominator:





(a/2) = 10


a = 20





3. B





All you have to do is plug in the values you were given:





A = 1/2h(a + b)


A = (1/2)(6)(5+7)


A = (3)(12)


A = 36





4. A





Let x = number of revolutions.





To find the number of revolutions for 15 minutes, you would multiply the number of revolutions in ONE minute by 15:





(300)*(15) = x





But this doesn’t look like any of your options. Try manipulating the equation a bit.





(300)*(15) = x





is the same as





x/300 = 15





5. C








Let A = Ann’s age and x = the age of the aunt. Then we want to solve:





1/5x = A





Now if we know Ann is 14, just plug in that value and solve for x:





1/5x = 14





Multiply by 5 to clear the denominator:





x = 70

radiata