Question

2 complementary angles are in such a way that twice one angle is thrice the other angle

Answer 1

let the angles be x and y
complementary angles add up to give 90°
thus
2x=3y,x=3y/2 - letthis be equation 1
x+y=90
3y/2+y=90 (by equation 1)
5y/2=90
5y=180
y=36
thus, x=54

Answer 2

let first angle is x and second be y

sum of complementary angles
 
x + y = 90..................(i)

ATQ 
2x = 3y
x=3y/2

Put x in eq (i)

 x + y = 90
3y/2 +y = 90

Now take LCM 
(3y+2y)/2 = 90
5y = 180
y=180/5
y = 36
put y in (i)
x + y = 90
 x + 36 = 90
x = 90 - 36
x = 54 

FIRST ANGLE =54
SECOND ANGLE = 36