1/8
Each time the probability for landing on heads in 1/2 or 50% so do 1/2*1/2*1/2=1/8.
(-1, 5) because if you plug in -1 to both equations, you should get 5 from both equations. They also cross at that point, making that the solution.
It's not perfectly clear, but you seem to be saying that each week, the
pond becomes 3% deeper than it was THE PREVIOUS WEEK.
If I'm reading that correctly, then the pond is 10-ft deep when the rainy
season begins, and after 'x' weeks later, the depth is
D = 10 (1.03)^x feet.
After 8 weeks, the depth is D = 10 (1.03)⁸ = 12.67 feet .
rounded to the nearest foot, D = 13 ft.
