What is the number?

Question

If 2 is added to a number and the sum is tripled, the result is 20 more than the number.
Please tell me how you solved it.

Answer 1

In other words, 3(x+2) = 20 + x

Solve for x:

remove the parentheses:
3x + 6 = 20 + x
subtract 6 from each side:
3x = 14 + x
subtract an x:
2x = 14
divide by 2:
x = 7

Answer 2

7.

Think of "the number" as y.

If 2 is added to y and the sum is tripled, the result is 20 more than y.

Now lets make it into real mathematical terms.

(2 + y) x 3 = y + 20

That may look confusing, but all its saying is 2 plus y multplied by 3 equals 20 more than y.

To solve this problem, we have to do a little guesswork and substitute real numbers for y. I tried 2 first.

(2 + 2) x 3 = 2 + 20

2 + 2 = 4. We have to substitute that into our problem:

4 x 3 = 2 + 20

4 x 3 = 12, and 2 + 20 = 22. 12 does not equal 22. Since the answer needs to be higher, we need to experiment with a higher number. Lets try 10.

(2 + 10) x 3 = 10 + 20

2 + 10 = 12. We need to substitute that into our equation.

12 x 3 = 10 + 20

12 x 3 = 36. 10 + 20 = 30. Although we're getting closer, 36 does not equal 30. We need a lower number. I decided to try 7.

(2 + 7) x 3 = 7 + 20

2 + 7 = 9. You know the drill, we need to substitute that into our equation...

9 x 3 = 7 + 20

9 x 3 = 27. 7 x 20 = 27. 27 is equal to 27! So the answer to your math problem is 7. =]

Answer 3

This can be written as: (2 + x) * 3 = 20 + x

To solve it, we just solve for x.

3(2 + x) = 20 + x

6 + 3x = 20 + x

2x = 14

x = 7

The answer is: 7.

I hope this helps.