Question

Billy plans to sell twice as many magazine subscriptions as Kayla. If Billy and Kayla need to at sell at least 90 subscriptions in all, how do you write and solve an inequality to determine how many subscriptions, `x`, Kayla needs to sell?

Answer 1

`x>= 30 implies` Kayla needs to sell at least 30 magazine subscriptions.

Explanation:

If Kayla sells `x` magazine subscriptions, and Billy sells twice as many, Billy sells `2x` subscriptions. Together they sell `x+2x = 3x` subscriptions. Since they need to sell at least 90 subscriptions together, we have the inequality:

`3x >= 90`

Now we need to determine `x` which is how many subscriptions Kayla needs to sell. We can do this by dividing both sides of our inequality by `3`:

`x>= 30`

Note that since we are multiplying/dividing by a positive number, the direction of the inequality stays the same. Therefore, Kayla needs to sell at least 30 magazine subscriptions.