Question

If ‘x’ varies inversely as y+2 and x=8 when y=2.5, find ‘x’ when y=4
2
4
6
8

Answer 1

Answer:

Set up an equation

x

=

1

y

substitute to find the constant

x

×

y

=

C

Then substitute again to find the new y

Explanation:

x

=

C

?

y

6

=

C

10

multiply both sides by 10

6

×

10

=

C

10

×

10

This gives

60

=

C

.

Now substitute x for 8 in the equation and 60 for C

8

=

60

y

multiply both sides by y

8

×

y

=

60

y

×

y

This gives

8

y

=

60

now divide both sides by 8

8

y

8

=

60

8

The answer is

y

=

7.5