VJesus12 wrote:If the charge of staying in a student youth hostel is $18.00/day for the first week, and $10.00/day for each additional week, How much does it cost to stay for 23 days?

A. $160
B. $289
C. $282
D. $274
E. $286

The OA is E .

Experts, how can I solve this PS question? What is the equation that I should use?

Hi vjesus12.

Let's take a look at your question.

We are interested in the cost of 23 days. We have to divide this 23 days as follows: 7 days (a week) + 16 days.

Then, the equation that gives us the cost total is: $$Cost=18\cdot\left(7\right)+10\cdot\left(16\right)=126+160=286\ \text{dollars}.$$ This is why the correct answer is the option [spoiler]E=$286[/spoiler].

I hope this answer can help you.

I'm available if you'd like a follow-up.

Regards.

23 days cost = 7 days * $18 + 16 days * $10
= $126 + $160 = $286

VJesus12 wrote:If the charge of staying in a student youth hostel is $18.00/day for the first week, and $10.00/day for each additional week, How much does it cost to stay for 23 days?

A. $160
B. $289
C. $282
D. $274
E. $286

The OA is E .

Experts, how can I solve this PS question? What is the equation that I should use?

Note, also, that once you get to this equation: 18*7 + 10*16, there's no need to actually solve, so we can save a little time.
18*7--> units digit of 6;
10*16 --> units digit of 0

Adding one term with a units of 6 to another with a units of 0 will give us a sum with a units digit of 6. Only E works.