mark is 10years older than his brother .in four years he will be twice as ld as his brother.find the present age

3 answers

M = Mark´s present age

B = Brother´s present age

Mark is 10 years older than his brother mean:

M = B + 10

After four years Mark will be M + 4 yrs old and brother wil bee B + 4 yrs old.

In four years he will be twice as old as his brother mean:

( M + 4 ) / ( B + 4 ) = 2

Now you must solve system:

M = B + 10

( M + 4 ) / ( B + 4 ) = 2

Try that.

The solution is:

M = 16 , B = 6
bro. is X yrs. old,
Mark is x+10 yrs. old.

In 4 yrs. :
(x+10) + 4 = 2(x+4),
x + 14 = 2x + 8,
X = 6 = Mark's bro. present age.
x+10 = 6 + 10 = 16 = Mark's present age.

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