Question

Two angles are supplementary and one of them is 4% less than 3 times the other

Answer 1

angle 1 = a, angle 2 = b

multiplying by 0.96 is the same as 4% less

a = 0.96(3b)

they are supplimentary meaning they add to 180

a + b = 180

solve for b

b = 180 - a

replace into other equation

a = 0.96(3(180 - a)

a = 0.96(540 - 3a)

solve for a from here. replace answer into a + b = 180 to get angle b.

Answer 2

two angles, assume one is x, the other one is 0.96*3*x=2.88x.
so since these are supplementary x+2.88x=180, 3.88x=180, x=46.39, 133.61