Pls help! will give brainlist!

The equations below represent the total amount charged, Y, by two different plumbers as a function of the number of hours worked, X.

Plumber A: y = 20x + 60
Plumber B: y = 40x

The graphs of these functions cross at the point (3, 120). What does the point (3, 120) signify?

A. The point (3, 120) is the slope of the system of equations.

B. The point (3, 120) is the Y intercept of the system of equations.

C. The point (3, 120) is the solution for the system of equations.

D. The point (3, 120) is when the plumbers worked 120 hours.

You have $600,000 saved for retirement. your account earns 5.5% interest. how much, to the nearest dollar, will you be able to pull out each month, if you want to be able to take withdrawals for 20 years?

How to do this , and can some one explain

With these 5 geometry questions! pls 1.)quadrilateral abcd is inscribed in this circle.what is the measure of ∠a ? enter your answer in the box.°2.)quadrilateral abcd is inscribed in a circle.what is the measure of angle a? enter your answer in the box.m∠a= 3.)quadrilateral abcd is inscribed in this circle.what is the measure of angle b? enter your answer in the box.m∠b= °4.)quadrilateral abcd is inscribed in this circle.what is the measure of angle a? enter your answer in the box.°5.) quadrilateral abcd is inscribed in this circle.what is the measure of angle c? enter your answer in the box.°