I=prt
1200=5000(3)r
1200=15000r
R=0.08
8% or 0.08
Use binomial distribution, with p=0.20, n=20, x=3
P(X=x)=C(n,x)p^x (1-p)^(n-x)
P(X>=3)
=1-(P(X=0)+P(X=1)+P(X=2))
=1-(C(20,0)0.2^0 (0.8)^(20-0)+C(20,1)0.2^1 (0.8)^(20-1)+C(20,2)0.2^2 (0.8)^(20-2))
=1-(0.0115292+0.057646+0.136909)
=1-0.206085
=0.793915
Simplifying
2(3(4 + p) + p) + p
2((4 * 3 + p * 3) + p) + p
2((12 + 3p) + p) + p
Combine like terms: 3p + p = 4p
2(12 + 4p) + p
(12 * 2 + 4p * 2) + p
(24 + 8p) + p
Combine like terms: 8p + p = 9p
24 + 9p