∠1∠1 and ∠2∠2 are a linear pair, and ∠2∠2 and ∠3∠3 are vertical angles. m∠2=(5+4y)∘m∠2=(5+4y)∘ and m∠3=(6y−25)∘m∠3=(6y−25)∘ . what is m∠1m∠1 ?

Linear pair of angles ads up to 180°. Vertical angles have same value.
According to this we have:
m<1 + m<2 = 180°
m<2=m<3

We can use this to solve for m<1.
m<2=m<3
5+4y=6y-25
4y-6y=-25-5
-2y=-30
y=15
m<2=5+4*15
m<2=65°

m<1 + m<2 = 180°
m<1 + 65° = 180°
m<1 = 180° - 65°
m<1 = 115°

If you divide 0.1 and 0.6 you wii get 0.166666 which rounds to .167 which is answer b