A dad has two daughters - wendy and julia. wendy is twice as old as julia. the man is now five times as old as wendy, and in 4 years he will be six times as old as julia. find the present age of the father.

X = age of julia

2x = age of Wendy

10x = age of dad (because dad is five times as old as Wendy)

(x+4) * 6=10x+4 (because in four years, that's why I added 4 to both sides, dad's age will be now 10x+4 and Julia's age x+4, now dad is 6 times as old and I multiplied Julia's age by six) = = > 6x+24=10x+4, now subtract 4 from both sides:

6x+20=10x, let's subtract 6x from both sides

20=4x = = > x=5

because age of father is 10x, we substitute x value and we get

10*5=50