This problem cannot be solved without additional information. Most likely, the triangle was a right triangle.
In that case the sum of the two acute angles is 90 degrees. Let the smaller of the two acute angles have measure x. Then the measure of the larger one is 5x.
This leads to the equation x + 5x = 90. Solution is x = 15.
So the smaller angle has measure 15, the larger has measure 75.