|
Question 490234: please help me solve:
ten times the sum of 30 and 15 is the same as the sum of a number and 12, what is the number?
Have tried: 10 x 30 = 300 + 15 = 315, 315 - 12 = 303 the number is 303
have tried: 10 x (30 + 15)= 450, 450 - 12 = 438 the number is 438
Answer by Theo(13342)   (Show Source):
You can put this solution on YOUR website! the problem is:
ten times the sum of 30 and 15 is the same as the sum of a number and 12, what is the number?
let x be equal to the number.
10 times the sum of (30 + 15) is equal to 10 * 45 which is equal to 450.
this is the same as the sum of a number and 12.
sum of a number and 12 is equal to x + 12 because we just assigned x to be equal to the number.
your equation becomes
450 = x + 12
subtract 12 from both sides of this equation to get:
450 - 12 = x which becomes:
438 = x
your number should be 438 if we did this right.
to confirm, assume your number is 438 and go back to the original problem and and see if it holds true.
the original problem statement is:
ten times the sum of 30 and 15 is the same as the sum of a number and 12, what is the number?
ten times the sum of 30 and 15 is still equal to 450.
the sum of 438 and 12 is equal to 450.
they are both equal to 450 so the problem statement holds true when the number is assumed to be 438.
looks like you got it right on the second try.
ten times the sum of 30 and 15 means you take the sum of 30 and 15 first and then multiply that by ten.
the key is the statement "the sum of"
that implies the sum has to be done before the multiplication.
|
|
|
| |
