Algebra Word Problem

[scistudent01]

Solve using N as the variable:
Find 2 consecutive integers whose sum is 79.
a) 76 and 77
b) 26 and 27
c) 39 and 40

[squarebear]

Hmm that's a tough one isn't it. Which of those adds up to 79?

[Tichfield]

79 divided by 2 = 39.5

So, I expect the answer is

39.5 minus 0.5, and 39.5 plus 0.5.

[squarebear]

Surely the answer jumps out at you from the options given?

[Tichfield]

lol

[Avatar]

X+y = 79
x = y -1
--

y = x+1 thus

x + x +1 = 79
2x +1 = 79
2x = 78
x= 39

[squarebear]

Wouldn't it just be easier to add up each of the numbers in the options given? There's only one that is even remotely close.

I hope this isn't the standard of maths they are teaching in schools nowadays.

[Prudie]

To give the answer in the way the question is worded is:

The 2 consecutive numbers are N and N+1
So
N+N+1 = 79
2N + 1 + 79
2N = 78
N =39
N+1 = 40

[Avatar]

Not as much fun as algebra though is it?

[Prudie]

Sorry, pressed the shift button, second line of equation should read
2N+1 = 79

[scistudent01]

Thank you all for your imput. No I am not a student, I am a mom who is "trying" to help my child with summer study in math and science. Which sad to say I haven't studied in either course in years! All help is truly appreciated! :o)

[derrynoose]

As algebra is generalised arithmetic I assume that the teacher is trying to help the child move from arithmetic calculations to thinking about the processes that underpin them. Good approach!