Question

When 3 is added to thrive a certain number and the sum is doubled the result is 13 more than 5 times the original number. Find the number

Answer 1

`-(7)/(3)`

Explanation:

Let the number = n

1. When 3 is added toa certain number ⇒ n + 3
2. the sum is doubled ⇒ 2(n + 3)
3. the result is 13 more than 5 times the original number ⇒ 2(n+3) - 5n = 13

2(n+3) - 5n = 13

2n + 6 - 5n = 13

-3n = 13 - 6

n = 7 ÷ (-3)

`n=-(7)/(3)`

Answer 2

Let's use algebra to solve this problem. Let the certain number be represented by the variable "x."

According to the problem:

When 3 is added to the number, we get x + 3.

When this sum is doubled, we get 2(x + 3).

The result is 13 more than 5 times the original number, which is 5x + 13.

So, we can set up the equation:

2(x + 3) = 5x + 13

Now, let's solve for x:

2x + 6 = 5x + 13

Subtract 2x from both sides of the equation:

6 = 3x + 13

Subtract 13 from both sides:

-7 = 3x

Now, divide by 3 to isolate x:

x = -7 / 3

So, the certain number is x = -7/3, which can also be written as -2.33 (rounded to two decimal places).