Question

Naomi works in a music shop and earns $42 per day. She earns an extra $2 for each CD she sells. If Naomi wants to earn at least $80 per day, which inequality shows the minimum number of CDs, n, that she should sell? (10 points)

42 + 2n ≤ 80, so n ≤ 19
42 + 2n ≥ 80, so n ≥ 19
42 + 2n ≥ 80, so n ≥ 36
42 + 2n ≤ 80, so n ≤ 36

Answer 1

First. 42 + 2n ≥ 80, so n ≥ 19

Explanation:

Because you see at least $80 so its just less or same 80. ANd we need to find the minimum number of CDs, but 36 is big, I choose 19.

Answer 2

42 + 2n ≥ 80, so n ≥ 19

Explanation:

Naomi's earnings for one day = $ 42,

Also, she earns extra $2 for each CD she sells,

Thus, the extra earning for n CDs = 2n dollars,

So, her total earning for a day if she sells n CDs = ( 42 + 2n ) dollars,

If Naomi wants to earn at least $80 per day,

Her total earning ≥ 80 dollars,