Q. If x and y vary directly and y is 4 when x is 2 , find y when x is 5 .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=4 when x=2. Substitute these values into the direct variation equation to find k. 4=k×2
Solve for k: Solve for k.Divide both sides of the equation by 2 to isolate k.k=24k=2
Write with k: Write the direct variation equation with the found value of k. Now that we know k=2, the direct variation equation is y=2x.
Find y: Use the direct variation equation to find y when x is 5. Substitute x=5 into the equation y=2x. y=2×5y=10
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