Question

If x and y vary inversely and x=15 when y=6,find y when x=9.

Answer 1

x inversely to y
y=k×1/x
xy=k.........(1)
x=15 & y=6
substitute in eqn (1)
15×6=k
90=k
when x=9 put eqn value of k and x
9×y=90
y=90/9
y=10

Answer 2

Answer:

If x and y vary inversely and x=15 when y=6, then y= 10 when x=9.

Step-by-step explanation:

Two quantities x, and y, are said to be in inverse proportion if they fulfill the following criteria:

If x increases, there is a decrease in y.

If x decreases, there is an increase in y.

x × y = k  (constant K)

If x = 15 and y = 6 then find k

k = x × y

= 15 × 6

k = 90

Now when k = 90, x = 9 find y

k = x × y

9 × y = 90

y= 90/9

y = 10

So, value of y = 10.