Maths question, help please

[GentleJones]

Can anyone tell me how to find the answer to this please:-

Chen is thinking of three numbers
He says,

The range is 5
The mode is 2

What are his three numbers?

Also

n stands for a whole number

2n is greater than 30
5n is less than 100

Write all the numbers that n stands for

I’ve checked the second question and believe you divide 30 by 2 and 100 by 5? but why do you do this? I know the answers are 16,17,18&19 but I’m not fully understanding why.

Thank you

1. 2 2 7
2. 16 17 18 19

Sorry, didn’t read properly! If n was 15 then 2n would be 30 which is not more than 30. If it was 20 then 5n would be 100 which is not less than 100. So n has to be the numbers between 15 and 20 to meet those two statements.

Thanks Wary but I could do with the methods too.

Thanks Wary, question one though, I’m at a complete loss.

And for the first one, the range is the difference between the largest and smallest numbers (so you subtract the smallest from largest). The mode is the most common number. He only has three numbers so two of them must be 2 for 2 to be the most common number. 7 must be the third as it is 5 more than 2, giving the range of 5.

THe mode is the most popular number so it would have to be 2 and 2. The range is between highest and lowest, so 2+5=7

Sorry x-post

The mode is the number which occurs most often, so if there are only 3 numbers, and the mode is 2 then two of the three numbers must be 2.

The range is the difference between the smallest and the biggest number, so take the smallest number (2) and add the range (5) to get 7

Thanks both of you.

I’m going to have to let this mode and range malarkey filter through slowly, I’m still not quite getting it. It will filter eventually but takes a bit longer than average

And -3,2,2 surely?

2n means times

So 2 x 15 = 30 so you are correct in dividing 30 by 2 to find 15 - as a starting point, but 2x15 isn't greater than 30 - so the next number is 16

Same for the other on

100 divided by 5 is 20 - so the next number it could be is 19

Agree, fredfredgeorge, there are 2 possible answers for the first question.

Although it's difficult to tell whether that was intentional. Suspect not given the way the question is worded.

Hey Diddle Diddle
The median's the middle
You add and divide for the mean
The mode is the number that shows up the most
And the range is the difference between.

Engraved on the heart of most year 6 children!!

Spanieleyes, thank you.

Ds states he’s never heard this before.

It's just a reminder, you do need to know a little about averages to work it out!
Median-the middle if you write the terms out in order
mean-add all the terms and divide by the number of terms
mode-the term with the highest frequency
range-the difference between the smallest and largest term

but it does help. I've invigilated SATS where the children have been muttering the rhyme under their breath as they've answered a question!

That’s great, thank you. Another useful piece of information to show Ds.

Makes sense that the answer could also be 2, 2 and -3

Thank you Spanieleyes

It will filter eventually but takes a bit longer than average

- Did you mean to make a pun?

Three types of average, politicians pick the one that gives them the answer they prefer most.

Mean - add them all up and divide by the number of things you had. this is the one most people think of when we use the term average.
Mode - the one that appears Most Often , (or the one that is most fashionable - as in 'a la mode' )
Median - put the items in size order and pick the middle one. if there are an even number of entries then choose the value half way between the two middle numbers.

Teen, bloody good aren’t I but no, the pun was not intended (but I shouldn’t have admitted that) but looking back it may have been subconscious 🤪

Thanks for the info, I’ll relate this to Ds.