Bob is 12 years younger than john. john is 3 times as old as bob. how old are bob and john.

John will be 16 years old when he is twice as old as his brother, which will then be 8.

Step-by-step explanation:

Currently John is 12, and is three times as old as his brother thus, his brother is 12 divided by 3, which is 4 years old.

Thus when John is 12, his brother is 4. There is thus a 8 year difference between the two brothers.

So we can write a small equation to solve John’s age when he will be twice as old.

John’s age = X

John’s Brothers age = X - 8

Thus : X - 8 = X/2, John’s age minus the difference of 8 years must equal John’s age divided by 2, to make John twice as old as his brother.

X - 8 = x/2

X = X/2 + 8

(2*X)/2 = (X/2) + (16/2) - Place all numbers as fractions of 2 by multiplying x 2

2*X = X + 16

2*X -X = 16

X+X -X = 16

X = 16

John’s age will be 16 when he is twice as old as his brother which will be 8.

John : 16 - 12 = 4 : Subtract current Age

His Brother: 8 - 4 = 4 : Subtract current Age

In 4 years time John will be twice as old as his brother

16 = 8 * 2

answ9x x 3=

step-by-step explanation:

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step-by-step explanation: