These are two math problems I need help with:

1. Tony paid the same price for a number of computer games totaling $138.25. Willy bought the same number of games for $117.25. Willy paid $3 less for each game than Tony did. How much did Tony pay for each game?

2. Damon gave Shaquan a 20-yard head-start in a race. Damon can run 3 yards a second while Shaquan can run 2.5 yards a second. Damon crosses the finish line 2 seconds ahead of Shaquan. How many yards did Damon run?

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1. Let x be the number of games for Tony and Willy, let y be the price per game for Tony and y-3 the price per game for Willy.

Tony:

xy=138.25

Willy:

x(y-3)= 117.25

xy-3x=117.25

138.25-3y= 117.25

-3x=-21

x=7

Substitute into Tony's equation:

7y=138.25

y=19.75

Tony paid $19.75 for each game.

2. Use the formula d=rt

Since this is a race to the finish line both runners run the same distance. Shaquan adds 2 seconds to his time because it takes him two seconds longer to run the same distance as Damon. Damon subtracts 8 seconds from his time because Shaquan had a 20 yard head start.

20yards/2.5yards/second=8 seconds

since d=d we can set rt=rt:

2.5(t+2)=3(t-8)

2.5t+5=3t-24

.5t=29

t=58s

d= 3(58-8) = 150 yards

1. Willy saved 21 dollars buying the same number of games.

138.25 - 117.25 = 21.00

Since the money he saved was $3 per game,

Money saved

-------------- = number of games each bought.

Money saved per game

21/3 = 7.

They bought 7 games each.

Tony:

$138.25/7 games = $19.75/game.

2.

Forgot about the head start!!!! :)

Distance = rate * time

They run the same distance D.

Let t be the time that it took Damon to run the distance.

Damon

D = 3yd/s * (t)

Shaquan took 2 seconds longer than Damon, so his time was t+2, and his distance was 20 yards shorter.

D - 20 = 2.5yd/s * (t+2)

Solve for D:

D = 2.5(t+2) + 20

Set them equal to each other:

3(t) = 2.5(t+2) + 20

3t = 2.5t + 5 + 20

3t - 2.5t = 25

.5t = 25

t = 25/.5 = 25*2 = 50s

That's the time for Damon.

The question wants the distance.

D = r*t

D = 3*50

Double check:

If D = 150, then Shaquan only had to run 150-20=130 yards, because he had a headstart.

If Damon ran the race in 50 seconds, and Shaquan took 2 seconds longer, then it took Shaquan 50+2 = 52 seconds.

Does that check out?

D for Shaquan = (2.5 yds/s)(52s) = 130yds. Check.

Michael H. | Tutor for Math and Computer SkillsTutor for Math and Computer Skills

1. Lets think about what this problem is telling us.

- Tony bought a number of video games (n) at a fixed price (p)
- The total of these games was $138.25
- We can write this as an equation:
- n*p = $138.25

- Willy bought the same number of games as Tony (n)
- Willy paid $3 less per game (p-3)
- Willy's total was $117.25
- This can be written as: n*(p-3) = $117.25

The problem asks us to find the price Tony paid per game (p)

- We have two equations and two variables in each.
- If we re-arrange the equations, we can get (n) on the left side of each
- n = 138.25 / p
- n = 117.25 / (p-3)

Now we have two different expressions for the value n, but we know that n = n

- So we can set the expressions for n equal to each other
- 138.25 / p = 117.25 / (p-3)

- At this point, we can solve the new equation for p
- 138.25 * (p-3) = 117.25 * p
- 138.25p - 414.75 = 117.25p
- 138.25p - 117.25p = 414.75
- 21p = 414.75
- p = 414.75 / 21 = 19.75

Tony paid $19.75 for each game

An alternate method:

- We can take the difference of the total prices ($138.25 - $117.25 = $21)
- Divide it by the price difference per game ( $21 / $3 = 7 )
- This is because the total difference divided by the per item difference will give us the count of items

- Therefore, each person bought 7 games.
- Now we can divide the total price paid by Tony by the number of games he bought (based on the equation from the first method):
- $138.25 / 7 games = $19.75 per game

You can use either of these methods to solve the second problem

Parviz F. | Mathematics professor at Community CollegesMathematics professor at Community Colle...

nP = 138.25

n(p-3) = 117.25

138.25 = 117.25

p p-3

P( 117.25) = p( 138.25)- 3( 138.25)

P( 138.25- 117.25) = 3( 138.25)

P = 3( 138.25 = 19.75

21

20/yd

S--------- D --------

2.5y/s 3.0Y/s

20 + 2.5(t+2) = 3 t

20 +5 = 3t-2.5t

25 = 0.5t t = 50 second

50* 3yd/s = 150yd Damon Yards

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