Question

If you double a number and then add 16 you will get 2/5of the original number. What is the original​ number?

Answer 1

Answer : x = -10

Step-by-step explanation :

x = original number

2x + 16 = 2/5x

Change 2/5 to decimal

2x + 16 = 0,4x

Change the position of 16 and 0,4x

2x - 0,4x = -1

Subtract 2 by 0,4

1,6x = -16

Divide -16 by 1,6

x = -10

You can use this way or the other one but this way is faster than the others

Hope it helps !

Answer 2

Explanation:

x = the original number

2x + 16 = 2/5 x

multiply both sides by 5 to get rid of the fraction :

10x + 80 = 2x

divide both sides by 2 :

5x + 40 = x

subtract x from both sides :

4x + 40 = 0

divide everything by 4 :

x + 10 = 0

subtract 10 from both sides :

x = -10