The cost of the book was at most three times the cost of the magazine. If the book cost $5.10, how much for the magazine have cost if none sell for more than $2.99?

Question

How do you set up the inequality for this problem:

The cost of the book was at most three times the cost of the magazine. If the book cost $5.10, how much for the magazine have cost if none sell for more than $2.99?​

Answer 1

Let the cost of the magazine be M. The book costs $5.10 and this value is no more than 3M so we can write 5.10≤3M and therefore 1.70≤M or M≥1.70. The magazine can’t be more than $2.99 so M≤2.99. That means M is between $1.70 and $2.99: 1.70≤M≤2.99.