Question

Two apps on your phone take away points for using your phone at school. You have 140 points on the first app and 80 points on the second app when a school day begins. Each time you check your phone, you lose 10 points on your first app and $p$ points on your second app. After you check your phone ten times, you have the same number of points on each app. Find the value of $p$

Answer 1

Answer: p = 4

Explanation:

For app one, you start with 140 points, and you lose 10 each time you check your phone.

Then, if you check your phone x times, you will have:

140 - x*10 points in total.

For app two, you start with 80 points, and you lose p points each time you check your phone.

Then, if you check your phone x times, you will have:

80 - x*p points left

We know that when x = 10, you have the same number of points in both apps, then we have the equation:

140 - (10)*10 = 80 - (10)*p

We can solve this for p

140 - 10*10 = 80 - 10*p

140 - 100 = 80 - 10*p

40 = 80 - 10*p

10*p = 80 - 40

10*p = 40

p = 40/10 = 4