Question

Ma. Lott’s works at a music store. Last week she sold 6 more than 3 times the number of CDs that she sold this week. Ms. Lott’s sold a total of 110 CDs over the 2 weeks. Which system of equations can be used to find x, the number of CDs sold last week, and y, the number CDs she sold this week.

Answer 1

`x=3y+6`

`x+y=110`

The number of CDs sold last week was 84 and the number of CDs sold this week was 26

Explanation:

Let

x ---> number of CDs sold last week

y ---> number of CDs sold this week

we know that

Last week she sold 6 more than 3 times the number of CDs that she sold this week

`x=3y+6` ----> equation A

Ms. Lott’s sold a total of 110 CDs over the 2 weeks

`x+y=110` ----> equation B

Solve the system by substitution

substitute equation A in equation B

`3y+6+y=110`

solve for y

`4y+6=110\\4y=110-6\\4y=104\\y=26`

Find the value of x

`x+26=110\\x=110-26\\x=84`

therefore

The number of CDs sold last week was 84 and the number of CDs sold this week was 26