SOLUTION: Find an equation of combined variation. Then solve for the missing value. w varies directly as x and inversely as y. One set of values is w = 3, x = 18, and y = 4. Find w when x

Algebra ->  Test -> SOLUTION: Find an equation of combined variation. Then solve for the missing value. w varies directly as x and inversely as y. One set of values is w = 3, x = 18, and y = 4. Find w when x      Log On


   



Question 1057348: Find an equation of combined variation. Then solve for the missing value.
w varies directly as x and inversely as y.
One set of values is w = 3, x = 18, and y = 4.
Find w when x = 12 and y = 4.

Found 2 solutions by Cromlix, MathTherapy:
Answer by Cromlix(4381) About Me  (Show Source):
You can put this solution on YOUR website!
Hi there,
w varies directly as x and inversely as y.
w = kx/y
k is the constant of proportion.
To find k use first set of values.
3 = k18/4
Cross multiply.
k18 = 12
k = 12/18
k = 0.67 (2 decimal places)
Formula:
w = 0.67x/y
Using the formula:
w = 0.67x/y
w = (0.67 * 12)/4 (* = times)
w = 2.01 (2 decimal places)
Hope this helps :-)

Answer by MathTherapy(10555) About Me  (Show Source):
You can put this solution on YOUR website!

Find an equation of combined variation. Then solve for the missing value.
w varies directly as x and inversely as y.
One set of values is w = 3, x = 18, and y = 4.
Find w when x = 12 and y = 4.
w+=+kx%2Fy
3+=+k%2818%29%2F4
3+=+18k%2F4_____3+=+9k%2F2
9k = 6 ------- Cross-multiplying
matrix%281%2C3%2C+k+=+6%2F9%2C+or%2C+2%2F3%29
w+=+kx%2Fy
w+=+%282%2F3%29%2812%29%2F4______w+=+8%2F4_______highlight_green%28w+=+2%29