X is inversely proportional to Y. When X=4, Y=9. If Y=6, what is the value of X?

There are a few steps to this question. Before we can work out our value of X we will have to figure out an equation that links X and Y.Now if X were proportional to Y, then as X got bigger so would Y.We can write this as: X≈Y (≈ substitute for proportional symbol)However they are inversely proportional, meaning that as X increases, Y decreases.We can write this as: X≈1/Yor: X=k/YWhere k is a constant representing the rate of change that we don't yet know. The rate of change is the amount X will decrease as Y increases, and likewise the other way round. Now we have our basic equation, we need to figure out what our constant k is. We can do this using the X and Y values provided in the question (4,9). Using these, we can write the equation as:4=k/9 (multiply both sides by 9 to get rid of the division)9x4=k (resolve)36=k OR k=36So now we can rewrite our original equation with the new k value as:X=36/YThe final step, now that we have our equation, is to work out our new value of X when Y=6. To do this we just need to plug the Y value back into the equation. So:X=36/6 (solve)So X=6And that's the answer to the question. (Good job!)

AW
Answered by Andrew W. Maths tutor

6278 Views

See similar Maths GCSE tutors

Related Maths GCSE answers

All answers ▸

How do you approach a simultaneous equations problem?


Solve the simultaneous equations: 4x + 7y = 1, 3x + 10y = 15.


John ran a race at his school. The course was measured at 450m correct to 2sf and his time was given at 62 econds to the nearest second. Calculate the difference between his maximum and minimum possible average speed. Round you answer to 3sf.


How do I expand out a pair of brackets?


We're here to help

contact us iconContact ustelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

MyTutor is part of the IXL family of brands:

© 2026 by IXL Learning