Question

10% of x° is the complement of 40% of 2x° find x

Answer 1

10% of x= x*10/100= x/10
⇒ 40% of 2x= 2x*40/100= 4x/5
threfore,x/10+4x/5=90
⇒x+8x/10=90
⇒9x/10=90
⇒x=100

Answer 2

10% of x° = 90 - 40% of 2x°

(10/100)×x° =90 - (40/100) × 2x°

x°/10= 90- 8x°/10

x°/10+8x°/10=90°

9x°/10 =90°

9x°= 90×10

x= (90×10)/9

x= 100°