Word Problems that SUCK

[bethanyninja]

I'm new to mathhelp.com, but i'm glad i found it

Anyway, here are the word problems I'm supposed to solve, and I don't even know how to start them!!

1. Roger's age is 1 and 1/3 times Steven's age. Eight years ago, Roger's age was twice Steven's age. Find Roger's age.



2. Amy is twice as old as Jenny. Five years ago, Amy was three times as old as Jenny. Find Jenny's age.


Thanks so much everyone!!!!!!!!!!!!!!!!!!

 

[mmm4444bot]

I have no idea what you already know about these types of exercises, or why you're stuck.

Read over THIS THREAD, and then come back here and tell me what you don't understand about it.

We'll go from there.

 

[FOREVERKODI]

Hi my name is Lexie, I am 19 and a sophomore in college. Anyways, I have been having a lot of trouble with word problems this semester so I would like to post one and ask that I get help!
Question: A chemist has 300 grams of 20% hydrochloric acid solution. He wishes to drain some off and replace it with an 80% solution so as to obtain a 25% solution. How many grams must he drain and replace with the 80% solution?

Thank you sooo much

I did have an equation and tried it out, but what I got made absolutely no sense. I am trying to assign variables, set up a chart and put the numbers in, I just can never get the right equation.

 

[mmm4444bot]

… I did have an equation and tried it out, but what I got made absolutely no sense. I am trying to assign variables …

Show me what you tried.

Or, explain what you're thinking.

Since this exercise asks for only one quantity, you only need to assign one variable.

 

[fasteddie65]

"Question: A chemist has 300 grams of 20% hydrochloric acid solution. He wishes to drain some off and replace it with an 80% solution so as to obtain a 25% solution. How many grams must he drain and replace with the 80% solution?"

I draw a picture of four containers: the first with 300 g 0f 20% solution; the second with x g of 20% solution; the third with x g of 80% solution; and the fourth with 300 g of 25% solution.

Work with the amounts of acid: 300(0.2) - 0.2x + 0.8x = 300(0.25)
60 + 0.6x = 75
0.6x = 15
x = 25

He must drain and replace 25 g.

 

[fasteddie65]

"1. Roger's age is 1 and 1/3 times Steven's age. Eight years ago, Roger's age was twice Steven's age. Find Roger's age."

Let a = Steven's age
and (4/3)a = Roger's age

a - 8 = Steven's age 8 yr ago
and (4/3)a - 8 = Roger's age 8 yr ago

(4/3)a - 8 = 2(a - 8)
(4/3)a - 8 = 2a - 16
8 = (1/3)a
24 = a
(4/3)a = 32

Roger is 32; Steven is 24.

8 yr ago, Roger