A box is filled with table-tennis balls. 4/9 of the balls are yellow. 60 balls are white and the rest of the 40 balls are pink. How many table-tennis balls are there in the box?

Answer 1

The total fraction of balls that are yellow and pink is 4/9 + 0 = 4/9 of the balls.
Let X be the number of tennis balls in the box.
So the amount of balls that are yellow and pink is (4/9)*X.
The rest of the balls, or (5/9)*X, are white.
So the total amount of tennis balls in the box is X = (4/9)*X + (5/9)*X = (9/9)*X = X.
And 60 balls are white, so (5/9)*X = 60 balls.
Thus, X = (9/5)*60 = <<(9/5)*60=108>>108 tennnis balls. Answer: \boxed{108}.