Suppose y varies directly as x and that y = 21 when x = 3. Find the value of y when x = 5.
Would I be wrong if I said y = 35? In using y = kx with the 21 and the 3 k = 7. So if y = 35 and x = 5 then k = 7. Am I correct or am I way off course?
To determine if your answer is correct, let's use the given equation y = kx, where y varies directly as x.
Given that y = 21 when x = 3, we can substitute these values into the equation: 21 = k * 3.
Solving for k, we divide both sides of the equation by 3: k = 21 / 3 = 7.
Now that we have the value of k, we can use it to find the value of y when x = 5. Plugging the values into the equation, we have y = 7 * 5 = 35.
Therefore, your answer of y = 35 is correct. Well done!
Your approach seems correct, but let's verify the answer using the given information.
The statement "y varies directly as x" can be mathematically represented as y = kx, where k is the constant of variation.
Given y = 21 when x = 3, we can substitute these values into the equation: 21 = k * 3.
Solving for k, we have k = 21 / 3 = 7.
Now, let's use this value of k to find y when x = 5: y = 7 * 5 = 35.
Therefore, your answer of y = 35 is correct. Well done!