A math question......
 

Math is not my best subject (only second worst to spelling!).

I'm going nuts trying to figure out how to do this.

How do I figure what % of 7 is 4.8?

It seems so simple, yet.......

:rolleyes:

I think it's 68.57%. You should be able to just divide 4.8 by 7.

I also am a heavy user of the cross-multiply and divide technique, which is a way I tend to represent "this is to this as that is to that" mathematically. So, you could cross-multiply 4.8 and 100 to get 480. Then divide that by 7 which equals the same thing I told you earlier. Sort of a 4.8 is to 7 as X is to 100 set up.

I think I made that more complicated than it needed to be.

Percentage couldn't be easier.

To find what percent A is of B:

A/B * 100

That's what I thought, but I was forgetting to multiply by 100 and wasn't sure if the 0.6857 was truley 68.57%.

Thanks guys, I knew I could count on you. :snap:

Brain melting.

Yep!

Yes - but you did make me smile. My Mom's theory of practical math is that everything that isn't simple arithmetic can be expressed in a ratio problem. And I've found very few examples where that wasn't true. Most of what I do know is making units cancel, which is another way of looking at ratios!

I totally use this method. It's the only way I can remember the relationships. It takes a few steps but it's always right :)

Maybe I am missing something, but I always believe it is better to KISS (Keep It Simple Stupid*). By adding steps, you introduce additional opportunities to make a mistake.

In the grand scheme of things, it doesn't matter all that much though.




* No, I am not calling anyone stupid: it is just the acronym

Yes, you do introduce opportunities - but if you're starting from a known correct place vs a potentially wrong place, it's better to go the long way around and double check for mistakes, then not know if you're in the right starting place.

Kevy, I'm pretty sure we've all heard the acronym by now... hehe ;) Anyone who hasn't probably needs to crawl out of that rock they've been living under.

On the other hand, I suspect that CP is more language person, such as myself. I have always done well in math, but because I relate it to something else - usually using vocabulary and logic type questions, kind of like the SATs. And like Drince said, it's better to take a little longer coming from the correct place than it is to go quickly from the wrong place.

Assuming a constant rate of water being added, if you overfill your old-fashioned clawfoot bathtub what will the upward velocity of your rubber ducky be at the moment the tub reaches capacity and begins to overflow?

What? That was what constituted practical math in my calculus classes.

But yeah, for figuring out percentages I use the cross multipication method. Or if an estimate is sufficient I would have said that since 7 is approximately 1/14th of 100 then just multiply 5 by 14 to get 70 and then subtract -- to get back to 4.8 from 5 -- .2 x 14 (2.8) to get an approximate answer (67.2%) which isn't all that far from the correct number (68.6%) and is all math that is easily done mentally.

Whereas I would have figured that 5/7 is a about 70% (70.173 or so I believe). .2/7 is about 2.8%, so yeah, the same ~67.2% as Alex gout (though I might have gone up to 68.5, figuring in that .173).

Ok, fine. I was being fancy. Realistically, I'm used to the number enough that off the top of my head I know that 4.66 is 2/3rds of 7 so I'd have said "a bit more than 67%."

So, as you see, there are all kinds of ways to approach the problem. Not the least valid of which is "ask on a message board."

As a nomination for "least valid" I nominated carving the question into the chest skin of a long-term comatose patient in hopes that they one day wake up and answer you.

Why am I thinking of African Swallows right now?

Laden or unladen?

What's wrong with the European ones?