Q. If x and y vary directly and y is 7 when x is 14 , find y when x is 8 .Answer: y=
Write Equation: Write the equation that represents the direct variation between x and y. Since y varies directly with x, the equation can be written as y=kx, where k is the constant of variation.
Find Constant: Use the given values to find the constant of variation k. We know that y=7 when x=14. Substitute these values into the direct variation equation to find k. 7=k×14
Solve for k: Solve for k.Divide both sides of the equation by 14 to isolate k.k=147k=0.5
Write with k: Write the direct variation equation with the found value of k. Now that we have found k to be 0.5, the direct variation equation is y=0.5x.
Find y: Use the direct variation equation to find y when x is 8. Substitute x=8 into the equation y=0.5x to find y. y=0.5×8y=4
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