can't find probability

Answer: [tex]0.0756,\ 0.7599[/tex]
Step-by-step explanation:
Given
Probability that a coin will land head is [tex]0.3[/tex] i.e. probability of success is [tex]p=0.3[/tex] So, the probability of failure is [tex]q=1-0.3=0.7[/tex]
Using Binomial distribution for [tex]n=4[/tex]
(a) Probability that the coin will lead heads exactly 3 times
[tex]\Rightarrow P(3)=^4C_3(0.3)^3(0.7)^1\\\Rightarrow P(3)=4\times 0.7\times (0.3)^3\\\Rightarrow P(3)=0.0756[/tex]
(b)Probability that the coin lands head at least once
[tex]\Rightarrow 1-P(0)\\\Rightarrow 1-^4C_0(0.3)^0(0.7)^4\\\Rightarrow 1-1\cdot(0.7)^4\\\Rightarrow 0.7599[/tex]