Question

If x varies inversely with y², and x=10 when y=7. find x when y=10

Answer 1

Statement says that,

x varies inversely with y²

According to the above problem,we get

x=k/y², where k is a constant

Now, x=10 when y=7, so the value of k is

10=k/7²

k=10×7²

k=10×49

k=490

Hence, when y=10,

we have to find the value of x

So by putting the value of k, we get

x=490/(10)²

x=490/100

x=4.9

★ x=4.9 is the right answer.

Answer 2

• 4.9

Explanation:

Given

x varies inversely with y², then the function is:

• x = k/y²

x = 10, y = 7, find the value of k by substituting the values of x and y:

• 10 = k/7²
• 10 = k/49
• k = 10*49
• k = 490

The function is:

• x = 490/y²

When y = 10, the value of x is:

• x = 490/10² = 490/100 = 4.9