Question

It costs Guido $0.20 to send a text message from his cell phone. He has already spent $4 in text messages this month. If he has a total of $10 that he can spend this month on text messages, write and solve an inequality that will give the greatest number of text messages that he can send. Interpret the solution.

Answer 1

Answer:
`x \leq 30` is the required inequality.

Explanation:

Let x be the greatest number of text message that he can do,

And, According to the question,

The cost of one text message = $0.20

And, Initially the amounts he has = $10

But, after spending $4 the remaining amount he has = 10 - 4 = $ 6

Now, total cost of the x messages = 0.20 x dollar

Again according to the question,

`0.20x \leq 6`

⇒
`x \leq (6)/(0.2)`

⇒
`x \leq 30`

Which is the required inequality.

By this we can say that he can do maximum 30 messages with the money he has.

Answer 2

`0.20x\leq 6`

`x\leq 30`

Explanation:

Given : cost of one text message = $0.20

the amounts he has = $10

he already spent $4

Solution:

the remaining amount he has after spending =10 - 4 = $ 6

So, Let the greatest number of text message that he can do be x

so,total cost of the x messages = 0.20 x dollar

as given in the question he cannot spend more than 10 dollar and at present he is left only with 6 dollar so right now he can spend only less than or equal to 6 dollar.

so inequality will be
`0.20x\leq 6` ---(A)

`x\leq (6)/(0.20)`

`x\leq 30`

Hence (A) is the required inequality.

So, he can do maximum 30 messages with $6.