Q. If x and y are in direct proportion and y is 4 when x is 8 , find y when x is 10 .Answer: y=
Write Equation: Write the equation that represents the direct variation between x and y. Since y varies directly with x, we can write the equation 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=8. Substitute these values into the direct variation equation to find k. 4=k×8
Solve for k: Solve for k.Divide both sides of the equation by 8 to isolate k.k=84k=0.5
Write Using k: Write the direct variation equation using the value of k. Now that we have found k to be 0.5, we can write the direct variation equation as y=0.5x.
Find y: Use the direct variation equation to find y when x is 10. Substitute x=10 into the equation y=0.5x to find y. y=0.5×10y=5
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