A father has a son and daughter. The father is five times as old as the daughter and the son is 2 years older than the daughter. In 10 years, the sum of their ages will be 81. How old are they now? Solve this problem by setting up an equation.

Question

anonymous · Answer

write that as an equation , and try to solve it

sidmanfu · Answer

im not really sure how to make it into an equation.

anonymous · Answer

lets name father ( f ) , daughter ( d ) and the son ( s )
f = 5 d 
s = d + 2 
(f+10) + ( s + 10 ) + (d + 10 ) =  81 
try to solve it !

anonymous · Answer

can u solve it ?

sidmanfu · Answer

Im stuck lol

anonymous · Answer

so, now that you got the equation, to solve it you need to keep only one unknown number 
f = 5d 
s = d + 2 
, any idea ?

sidmanfu · Answer

sorry but I have no idea

anonymous · Answer

how much is d  in terms of s ?

sidmanfu · Answer

added by 2...

anonymous · Answer

thats s in terms of d , we need d in terms of s ))

sidmanfu · Answer

ohh
is it 2 year younger?

anonymous · Answer

yes so , d = s - 2 ,
so  f = 5 ( s - 2 ) 
right ?

sidmanfu · Answer

yes thats right

anonymous · Answer

now simplify that f = 5( s - 2 ) , and get me s in the terms of f

sidmanfu · Answer

so is $$f = 5s - 10$$ ?

anonymous · Answer

yes , now get s in terms of f 
s = ??