Question

twice a number plus another number is 310. The difference between the two numbers is 55. What are the two numbers

Answer 1

Lets say the first number is x and the second y

twice the first number is 2x plus another number (y) =310
the difference of the numbers (x-y) = 55
we have simultaneous equations here:
2x+y=310
x-y=55

to cancel the y's the signs are different so you add the equations to give
3x=365
divide it by 3 to get:
x=121 and 2/3

using the easier equation x-y=55 we know x=121 2/3
now we substitute to get 121 2/3 -y=55
take 121 2/3 from both sides to get:
-y= -66 2/3
therefore y= 66 2/3

that means x=121.6(recurring) and y= 66.6(recurring)

Answer 2

T us assume the two numbers to be "x" and "y".
Then
2x + y = 310
And
x - y = 55
Let us take the second equation and find the value of x in relation to y.
x - y = 55
x = y + 55
Now let us put the value of x in the first equation, we get
2x + y = 310
2(y + 55) + y = 310
2y + 110 + y = 310
3y = 310 - 110
3y = 200
y = 200/3
   = 66 2/3
Now putting the value of y in the second equation, we get
x - y = 55
x - (200/3) = 55
3x - 200 = 55 * 3
3x = 165 + 200
x = 365/3
   = 121 2/3
So the value of x is 121 2/3 and the value of y is 66 2/3