Three friends all have ages that are consecutive integers. The sum of their ages is 57. What is the age of the oldest friend?

Friend C would be 20 years old

Step-by-step explanation:

Consecutive integers are integers that follow each other

In this case, we have three friends (let's call them A, B, and C) who's total age sum is 57:

A + B + C = 57

If Friend B is one year older than Friend A and Friend C is two years older than Friend A (or one year older than Friend B), then we write and solve for Friend A:

A + (A + 1) + (A + 2) = 57

3A + 3 = 57

3A = 54

A = 18

So if Friend A is 18 years old, then Friend B is 19 years old, and Friend C is 20 years old, making Friend C the oldest.

20 years old

Step-by-step explanation:

3x + 3 = 57

3x = 54

x = 18

X + 2 = 18 + 2

Answer = 20 years old

let's add {f(x)=x+1}f(x)=x+1 and {g(x)=2x}g(x)=2x together to make a new function.

f(x)+g(x) =(x+1)+(2x)=x+1+2x=3x+1

let's call this new function hh. so we have:

{h(x)}={f(x)}+{g(x)}{=3x+1}h(x)=f(x)+g(x)=3x+1

we can also evaluate combined functions for particular inputs. let's evaluate function hh above for x=2x=2. below are two ways of doing this.

method 1: substitute x=2x=2 into the combined function hh.

h(x)

h(2)

​    

=3x+1

=3(2)+1

=7

​ since h(x)=f(x)+g(x)h(x)=f(x)+g(x), we can also find h(2)h(2) by finding f(2) +g(2)f(2)+g(2).

first, let's find f(2)f(2):

f(x)

f(2)

​    

=x+1

=2+1

=3

​  

now, let's find g(2)g(2):

g(x)

g(2)

​    

=2x

=2⋅2

=4

​  

so f(2)+g(2)=3+4=\greend7f(2)+g(2)=3+4=7.

notice that substituting x =2x=2 directly into function hh and finding f(2) + g(2)f(2)+g(2) gave us the same answer!