GED Questions from Jesse

Jesse writes:I was wondering If u could let me know if I got these two questions correct I’m taking my ged next week & I want to feel comfortable with this math.
On a map 1/3 in=15 miles find the distance between two towns on a map that equals 3 2/3 in. How many miles r between the two? my answer was 75 miles am I correct?Next Question

The scale on a map indicates that 1/2 inch represents an actual distance of 120 miles, how far apart will two towns be if the actual distance between them is 180 miles my answer was 2 inches am I correct? if not could u explain how to set up these type of problems? thank you, Jesse.

Jesse,

Hey! Congrats on your GED test comin’ up. Y’know what these questions are? Ratios. I got a ratio post on my blog at: http://www.passged.com/student_blogs/curtis/2007/12/24/rice-ratios-gotta-love-that-ged-math/

There’ll prolly be a ratio question on the GED test. Here’s how it works. Take the first question. You got 1/3 inch, that equals 15 miles. Picture it in your head. Say this line is 1/3 inch: |—| It be 15 miles.

So, you got to find out how many miles in 3-2/3 inch. Well, first you gotta find out, how many 1/3-inches are in 3-2/3 inch. Get it?

Three 1/3-inch lengths are in 1 inch, like this:
|—|—|—|

So, in 3-2/3 inches, there’s 11 1/3-inch lengths:
|—|—|—|
|—|—|—|
|—|—|—|
|—|—|

Each 1/3-inch is 15 miles, right? So, we got 11 lengths of 15 miles… that’s 15 times 11, and that’s 165 miles! There ya go. Always makes it easier to understand to picture it in your head.

If you want to do it mathematically, what I did was set up a ratio:
1/3:15
3-2/3:x

Divide 3-2/3 by 1/3… then multiply 15 by the answer to get x.

Here’s the other one.
1/2 inch = 120 miles
x = 180 miles

Same deal here, right? You got a ratio.
1/2 inch:120 miles
x:180 miles

The relationship between 120 and 180 got to be the same as between 1/2 and the answer. So, what’s the relationship between 120 and 180? If you divide 180 by 120, 180/120 = 18/12 = 9/6 = 3/2 = 1-1/2

So, 180 is 1-1/2 times 120. Then x got to be 1-1/2 times 1/2. That’s 3/4. If it’s easier, you can do 1.5 x .5 = .75 …same thing. So, the answer’s 3/4 inch. Get it?

Hope this helps!

Curtis

For more information about the GED test and GED test preparation, visit The GED Academy at http://www.passged.com.

GED Math: Taking a Closer Look

S’up y’all. Ready for some more GED Math?

I been thinkin’ about how sometimes we think we know the answer without looking at the whole problem, you know? Check this out.

Super Subs Inc. is planning on hiring new employees for the summer. They want to make sure their new employees are available to work on the busiest day of the week. Below is a chart of their four different stores, and how many sub sandwiches they sold at each store the previous week. According to this chart, which day will the new hires most likely need to work?

chart_sub_sandwiches

Continue reading

More GED Math: Algebra

Okay, still some confusion all over about algebra. It’s tough, cuz it’s what’s called abstract. Those x’s ain’t exactly somethin’ concrete. Here’s a run-down of some basic workin’ with x’s….

Algebra’s like a puzzle. Know those puzzles where you gotta move the pieces around to make a picture? It’s like that. To find what number “x” is, you gotta move the numbers around, so that “x” is by itself on one side. And there’s rules. Here’s the key: you have to do the same thing to both sides of the equation.

So, if x + 3 = 5 and you want x by itself, you’ve got to “zero out” the + 3. To make the + 3 cancel out, you’ve got to subtract 3. That means you’ll have 3 – 3 on the side with the x, and 3 – 3 is 0, and 0 is nothing. That’s what you want… nothing with the x.

But, if you want to subtract 3 from the left side, you gotta subtract 3 from the right, too, to keep ’em equal.

x + 3 = 5
x + 3 – 3 = 5 – 3
x + 0 = 2
x = 2

Okay, that’s the easy part. Hard part is, if you got x’s on both sides.

2x = x + 5

What do I want to do? Subtract x from both sides, to get rid of the x on the right (x – x is the same as 3 – 3 or 23 – 23…. it’s zero).

2x = x + 5
2x – x = x – x + 5
2x – x = 0 + 5
2x – x = 5

Now, what’s 2x – x? The shorthand rule is, you subtract (or add) the numbers by the x’s, and leave the x alone. “x” without a number has an invisible “1” next to it. So:
5x – 3x = 2x
22x + 5x = 7x
x + x = 2x
5x – x = 4x

That means, if 2x – x = 5, then x = 5.

Here’s why. 5x means 5 times x. And 5 times x means x + x + x + x + x. That’s what multiplication is, a shorthand way to add a number plus itself a bunch of time.
5 × 9 = 9 + 9 + 9 + 9 + 9
5x = x + x + x + x + x

So, 2x – x means x + x – x. Two of the x’s cancel out (x – x = 0). So, it’s x + 0, or just plain x.

2 x’s minus 1 x is… 1 x. Just like if you got 2 apples and take away 1 apple, you got one apple left.

So, here’s a problem:

5x + 14 = 3x + 22

I can subtract 14 from both sides to move all the numbers to the right…
5x = 3x + 8

Now, I can subtract 3x from both sides to move all the x’s to the left…
2x = 8

The last step, since x is multiplied by 2, is divide both sides by 2 to get the x by itself….

x = 4

There ya go!

GED Math: Casio Calculator

Hey, all. Qweenbe wrote in askin’ about the calculator for the GED test… and I’d been meanin’ to do a post about it.

See, it’s a scientific calculator with all kindsa cool functions that you don’t need on the test. It’s important to know how to use it so you don’t hit the wrong order of buttons and get the wrong answer. And the better you gonna get with the calculator, the faster you can do the math. Continue reading

GED Math: Algebra

Here’s a problem that Lyndia sent in, since she was havin’ trouble with it:

3x = 7 – 4x

You wanna figure out what “x” is equal to The problem comes in when you have a number befo’ the x, and need to get all the “x”es on the same side. Think of it this way… you don’t just got one x, you got four x’s. So, you gotta move all 4 x’s to the other side. In other words, think of “4x” as all going together. Continue reading

GED Math: Adding and Subtracting Fractions

Hey, all. Michael’s studyin’ for his GED, an he sent me this question:

am having problem with Lesson-7 page 491 on A. on Add or subtract as Directed reduce to the lowest terms.Am trying to figure out the form to work the fractions. am stuck on this one. Michael

Okay, here’s the rule with adding and subtracting fractions. Let’s start with a problem:

5/12 + 2/5 Continue reading