Help with homework:Math

[TJ10]

Subject:Let Statements.
Dont tell me the answer,Just tell me the Let statements and the equation i have to solve.
I am clueless on these:

1.)Jacob finished a 42-mile race in 3 hours.He ran for average rate of 7 miles per hour and Biked for 22 miles per hour.How much time did he run and bike?(That isnt full question,Just important info)

2.)Jason Cooke bought 25 stamps,valued 37 and 39 cents.He paid with a 20 dollar bill.$10.45 change back.How many 37 and 39 cent stamps did he get?

Please help me.

[Ad Bot]

[Edman]

5 

[NinjaMaster]

paided

Ha ha ha, but in all srsness. Going to a forum for homework help? Ask your parents.

[The Doctor]

Wow, Jacob needs to be in a marathon race if he can run 42 miles in 3 hours, And Jason, go somewhere else where stamps are cheap, dude.

[TJ10]

Parents dont know stuff.My mom even said she didnt have a clue,

Can there be more serious in this topic.

[The Doctor]

Parents dont know stuff.My mom even said she didnt have a clue,

And if he can bike 22 miles in 3 hours, he a natural!

[Unwritten Calender]

what grade are you in?
4th?

[Kingdaro]

2)

x + y = 25
37x + 39y = 955 (What he paid, decimals removed.)

  37x + 39y = 995
*-37x - 37y = 25

-1443y = 24875
y = -17.24

x - (17.24) = 25
x = 25 + 17.24

...Yeah, I'm wrong. :/

[TJ10]

Actually 9th, Didnt pay much attention to this.

[The Doctor]

1) He ran for 14 miles, biked for 3.1 miles.

2) 76

[Kalphiter]

Wow, Jacob needs to be in a marathon race if he can run 42 miles in 3 hours, And Jason, go somewhere else where stamps are cheap, dude.

NYC Marathon is 16 miles and it was done in over 2 hours.
Assuming the same speed, the fastest runner can do 42 miles in 6.125 hours.

[The Doctor]

NYC Marathon is 16 miles and it was done in over 2 hours.
Assuming the same speed, the fastest runner can do 42 miles in 6.125 hours.

Good point.

[Otis Da HousKat]

These are systems of equations problems they are set up in the following manner:

*editing in as I make them to get in before 50 more handicaps post*

1) Let x = time on foot, y = time on bike

x+y=3
7x+22y=42

2) Let x = 37 cent stamps, y = 39 cent stamps

x+y=25
37x+39y=955

[Sebster 105]

Why don't you tell them your dog ate it?

[Makingblah]

I would use simultaneous equations.. But I'm not sure.

Let me try..

1.)Jacob finished a 42-mile race in 3 hours. He ran for average rate of 7 miles per hour and Biked for 22 miles per hour. How much time did he run and bike?

Let x be cycled, and y be ran.

x + y = 3
22x + 7y = 42

-7x + -7y = -21
22x + 7y = 42

15x = 21
x = 1.4

1.4 + y = 3
y = 3 - 1.4

y = 1.6

1.4 x 22 = 30.8
1.6 x 7 = 11.2

30.8 + 11.2 = 42.

The answer is Jacob ran for 1.4 hours and cycled for 1.6 hours.