2007-01-09 11:27:34 · 8 answers · asked by ashley f 1 in Science & Mathematics ➔ Mathematics
Let the unknown number be N.
So,
N + 1/2N = 45
2(N + 1/2N) = 2 (45)
2N + N = 90
3N = 90
N = 30
2007-01-09 11:32:45 · answer #1 · answered by e_kueh 2 · 0⤊ 0⤋
Let x = the number in question.
Then, the sum of the number (x) and half of the number (1/2)x is 45. Translating that algebraically,
x + (1/2)x = 45
Factor out x on the left hand side,
x(1 + 1/2) = 45
Solve the brackets,
x(3/2) = 45
Multiply both sides of the equation by 2/3,
x(3/2)(2/3) = (2/3)45
x = 90/3
x = 30
2007-01-09 19:32:39 · answer #2 · answered by Puggy 7 · 0⤊ 0⤋
Let's call our missing number x. Think about what the problem asks: a number plus half of that same number equals 45. The equation would look something like this:
x + .5x = 45
First, add the two variables to get this:
1.5x = 45
Divide both sides by 1.5 to get x by itself and you'll get x = 30.
To see if 30 works, plug it back into the original equation.
30 + .5(30)
30 + 15
45
Your missing number is 30.
2007-01-09 19:36:35 · answer #3 · answered by AskerOfQuestions 3 · 0⤊ 0⤋
X + X/2 = 45
multiply both sides by 2 to get rid of the fraction.
2X + x = 90
3X = 90
Divide both sides by 3 to isolate X
X = 90/3
X = 30
Check:
30 + 1/2(30) =
30 + 15= 45
2007-01-09 19:35:20 · answer #4 · answered by Joseph F 5 · 0⤊ 0⤋
x + x/2 = 45
3x/2 = 45
3x=90
x =30
Check: 30 + 30/2 = 30 +15 = 45
2007-01-09 19:32:31 · answer #5 · answered by ironduke8159 7 · 1⤊ 0⤋
x + x/2 =45
2x + x = 90
3x = 90
x= 30
2007-01-09 19:32:01 · answer #6 · answered by Antonio R 3 · 0⤊ 0⤋
30+.5(30)=45
30+15=45
45=45
2007-01-09 19:39:15 · answer #7 · answered by Tiffany E 1 · 0⤊ 0⤋
x+1/2x=45
3/2x=45
x=30
2007-01-09 19:33:34 · answer #8 · answered by 7 · 0⤊ 0⤋