Direction : What value should come in the place of question mark (?) in the following questions?

23 × 45 ÷ 15=?

What is the reflection of the point (-3, 1) in the line x = -2? 

What is the equation of the line whose y-intercept is -3/4 and making an angle of 45 ° with the positive x-axis? 

What should come at place of question mark (?) in the following number series?

1.7 5.4 19.2 80.8 409 ?

What will be remainder if (13)³ is subtracted from (66)² ?

Find the sum of 30²+31²+32²+________+80²

Ram sold an article for Rs 380 at some profit. Had he sold it for Rs 300, then there would have been a loss equal to one-third at the initial point. What was the cost price of the article? 

A does half as much work as B in one-third of the time taken by B. If together they take 10 days to complete a work, then the time take by B alone to do it would have been__