Q. If x and y vary directly and y is 60 when x is 10 , find y when x is 15 .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=60 when x=10. Substitute these values into the direct variation equation to find k. 60=k×10
Solve for k: Solve for k.Divide both sides of the equation by 10 to isolate k.k=1060k=6
Write with k: Write the direct variation equation with the found value of k. Now that we know k=6, the direct variation equation is y=6x.
Find y for x=15: Use the direct variation equation to find y when x is 15. Substitute x=15 into the equation y=6x to find y. y=6×15y=90
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