Word Problems?

Question

If anyone could help me with these word problems I have that would be VERY helpful! Also, if you could go through them step by step that would be great. thanks!

#1- Eight times a certain number is egual to 32 less than three times the same number. Find the number.

#2- An executive's salary is now $152500. This is two and a half times his salary 4 years ago. Find his salary 4 years ago.

#3- Find the amount of principal invested if the amount after 2 years was $3373.83 and the interest rate was 7%. Use A=P+PRT

#4- A bacteria culture has 12600 bacteria at 10 a.m. This is a decrease of 32% from the number at 7 a.m. How many bacteria were in the culture at 7 a.m.

Thank you all! I didn’t have any way to check my answers; therefore, I was pretty unsure of how to do them. Plus word problems are my arch enemy! Thanks again!

Answer 1

Alright, these aren't that tough. I'll start you off with the first two.

8x = 3x - 32
-5x = 32
x = -6.4

Problem 2:

152500/2.5 = y
y = $61,000
(another way to read this is that she's now receiving 2 1/2 times what she was receiving 4 years ago - so divide what she's receiving now by 2.5)

Answer 2

#1) let x : the number
8x = 3x - 32
8x - 3x = 3x - 32 - 3x
5x = -32
5x/5 = -32/5
x = -6.4

#2) let x : salary 4 years ago
2.5x = 152500
2.5x/2.5 = 152500/2.5
x = 61000

#3)
7% = 7/100 = 0.07
2 : time in years
x : principal amount
x + x (0.07) 2 = 3373.83
x (1.14) = 3373.83
x(1.14)/1.14 = 3373.83/1.14
x = $2959.50

#4)
100% - 32% = 68% : bacteria left at 10 am
68% = 68/100 = 0.68

let x : bacteria at 7 am
0.68x = 12600
0.68x/0.68 = 12600/0.68
x = 18529.41176; rounded off to the nearest integer:
x = 18529

Answer 3

I'll give you a start. You need to substitute x for the unknown. In problem 1 you don't know what the certain number is so put x in. 8x = 3x-32. Solve for x.

Answer 4

#1 8x = 3x-32 (are you sure?)sounds wrong

#2 $152,500/2.5 = X


#4 12,600/.68 = X

Answer 5

Here's a swell idea. Do your own homework!