15.2 is 2 times as large as some number.

Question

What is the number?

Answer 1

15.2 is twice as large as some number means that that number you want to find is half of 15.2.

 

Half of 15.2 is 7.6.

 

 

If I'm a 12 foot tall giant and I'm about twice as tall as a normal person, how tall is a normal person? How did you figure that out?

 

If I have 10 fingers and that's two times more than someone who's missing a hand, how many fingers does someone missing a hand have? How did you figure that out?

 

Saying that one thing is double another is the same thing as saying that other thing is half of the first thing. 

 

If I bury 84 acorns before the winter every year and that's twice as much as anyone else buries, how many acorns does some other person bury? How do you know?

 

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If you have to set up an equation, then 15.2 = 2x is a good choice. 

 

You can use this for any ratio in a question like this. 

 

Like, if I asked: 17 is three times bigger than this other number, what is it?

 

You would know that number is a third of 17. Or you could write a statement like 17 = 3x.

 

If I said something harder like 99.4 is 5/4 of another number, you'll want to resort to writing an equation, but still reason it out the same. 

 

"99.4 is" means 99.4 = 

 

"5/4 of another number" means some number times 5/4.

 

You can put these phrases together and you'll get what you're looking for: 99.4 = (5/4)x.

 

 

 

x represents the number you don't know.

 

Answer 2

Hi Briana

 

Think of the word "is" as your equal sign and then write what you know

 

15.2 = 2n

where n is the number you're looking for.

 

Now solve for n by dividing both sides by 2

7.6 = n