In the adjoining figure, line l is parallel to m. What is the value of 2x + y?

Correct option is B

Given: 

line l is parallel to line m.

Concept Used: 

If two line are parallel to each other, then alternate angle are equal to each other.

Sum of angle made on a straight line = $$180^\circ$$ 

Solution: 

​$$\angle a + 60^\circ = 180^\circ$$ (angle on straight line)

$$\bf \angle a = 180^\circ - 60^\circ = 120^\circ$$ 

$$\angle y = \angle a = 120^\circ \quad(\text{alternate angles})$$ 

$$\angle b = 105^\circ \quad(\text{alternate angle})$$ 

$$\angle b + \angle x = 180^\circ \quad \text{(straight angle}) \\ \bf \angle x = 180^\circ - 105^\circ = \bf 75^\circ$$ 

So, 

​$$2x+y = 2\times 75 + 120 = \bf270^\circ$$​​