Question

Since 2002, the number of a telephone company’s customers using a landline has been decreasing by 10% per year. Which of these statements are correct? Select all that apply.

1. To find the number of landline customers in 2004, you can multiply the number of landline customers in 2002 by 0.81.
2. To find the number of landline customers in 2004, you can subtract the product of 0.2 and the number of landline customers in 2002 from the number of landline customers in 2002.
3. To find the number of landline customers in 2003, you can multiply the number of landline customers in 2002 by 0.9
4. To find the number of landline customers in 2003, you can subtract the product of 0.1 and number of landline customers in 2002 from the number of landline customers in 2002.

Answer 1

1 and 3 I believe are the correct answers

Answer 2

Option 1 , Option 3 and Option 4 are correct.

Explanation:

Number of customers using landlines decreases 10% per year.

Let x be the umber of customers using landlines in 2002.

⇒ Number of customer using landlines in 2003 =
`x-(10)/(100)* x`

=
`x-0.1x`

= 0.9x

Number of customers using landlines in 2004 =
`0.9x-(10)/(100)* 0.9x`

=
`0.9x-0.1*0.9x`

=
`0.9x-0.09x`

=
`0.81x`

Therefore, from this Option 1 , Option 3 and Option 4 are correct.