A bag contains n counters. One counter is yellow and the rest are green.
Two counters are taken at random from the bag.
a) Express, in terms of n, the probability that both counters are green.
Give your answer as a fraction in its simplest form.
b) The probability that both counters are green is 0.9
How many green counters are in the bag?

Astudent draws two parabolas on graph paper. both parabolas cross the x-axis at (-4, 0) and (6,0). the y-intercept of thefirst parabola is (0, –12). the y-intercept of the second parabola is (0-24). what is the positive difference between the avalues for the two functions that describe the parabolas? write your answer as a decimal rounded to the nearest tenth.

Use the method of cylindrical shells to find the volume v generated by rotating the region bounded by the curves about the given axis. y = 7ex, y = 7e^-x, x = 1; about the y-axis

Estimate the time en route from majors airport (area 1) to winnsboro airport (area 2). the wind is from 340° at 12 knots and the true airspeed is 136 knots. magnetic variation is 5° east.