Math Is Fun Forum

KarishmaChandock

Guest

Grade 6 National Talent Search Examination

Please help solve

If

5² + 5³ = 6
6² + 6³ = 9
7² + 7³ = 5

Then 8² + 8³ = ?

Options
A) 7         B) 5         C) 9        D) 4

Bob

Administrator

Registered: 2010-06-20

Posts: 10,196

Re: Grade 6 National Talent Search Examination

hi KarishmaChandock

Welcome to the forum.

At the top of the Help Me section it says Read This Before Posting and in that post "We are happy to help! But we don't do your homework for you. "

How about you tell us what you have tried so far? If you've made a good effort I might give you a hint as you may be lacking specific knowledge that would complete the task.

Bob

---

Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

nycguitarguy

Member

Registered: 2024-02-24

Posts: 542

Re: Grade 6 National Talent Search Examination

Please help solve

If

5² + 5³ = 6
6² + 6³ = 9
7² + 7³ = 5

Then 8² + 8³ = ?

Options
A) 7         B) 5         C) 9        D) 4

Let me see.

1) 5² + 5³ = 25 + 125 = 150

150 ÷ 25 = 6

2) 6² + 6³ = 36 + 216 = 252
   
252 ÷ 36 = 7

3) 7² + 7³ = 49 + 343 = 392

392 ÷ 49 = 8

Now, to find 8² + 8³:

4) 8² = 64
5) 8³ = 512
6) 8² + 8³ = 64 + 512 = 576

576 ÷ 64 = 9

My answer is choice C.

Last edited by nycguitarguy (2024-04-14 15:07:21)

Bob

Administrator

Registered: 2010-06-20

Posts: 10,196

Re: Grade 6 National Talent Search Examination

hi nycguitarguy

This is a talent exam question so I decided I was not going to provide an answer.

I started the same way as you but

3) 7² + 7³ = 49 + 343 = 392

392 ÷ 49 = 8

and the given 'answer' is

7² + 7³ = 5

So this isn't the way to work these out.  If you do find an answer, please don't post it for the reason given above.

Bob

---

Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

nycguitarguy

Member

Registered: 2024-02-24

Posts: 542

Re: Grade 6 National Talent Search Examination

hi nycguitarguy

This is a talent exam question so I decided I was not going to provide an answer.

I started the same way as you but

3) 7² + 7³ = 49 + 343 = 392

392 ÷ 49 = 8

and the given 'answer' is

7² + 7³ = 5

So this isn't the way to work these out.  If you do find an answer, please don't post it for the reason given above.

Bob

Thanks Bob. I know now for next time. In any case, can you tell me what I did wrong?

Bob

Administrator

Registered: 2010-06-20

Posts: 10,196

Re: Grade 6 National Talent Search Examination

You're correct that the calculation comes to 8.  But the problem in post 1 says it has to come to 5. So your arithmetic is good but you haven't decoded the puzzle. It is possible to find a way to get 5. That's what makes it a worthy puzzle.

Bob

---

Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

nycguitarguy

Member

Registered: 2024-02-24

Posts: 542

Re: Grade 6 National Talent Search Examination

You're correct that the calculation comes to 8.  But the problem in post 1 says it has to come to 5. So your arithmetic is good but you haven't decoded the puzzle. It is possible to find a way to get 5. That's what makes it a worthy puzzle.

Bob

Thank you, Bob.