Jafar10 wrote:
The answer is D:
Out of three people 2 buy candy pack. The 3rd person don't.
Buy = 0.3
Not buy = 0.7
Then ---》 2*(0.3)*0.7 =0.063.
Posted from my mobile device
Actually, the answer has to be C.
You must multiply 0.063 by (3!/2!), which equals 3, to get 0.189.
So, the equation will be : (0.3)^2 * 7 * (3!/2!)
These are the three ways in which the favorable event can take place (B=Buy, N=Not Buy)
BBN = 0.063 (First & Second person buys | third doesn't buy)
BNB = 0.063 (First & Third person buys | second doesn't buy)
NBB = 0.063 (Second & Third person buys | first doesn't buy)
Total = 0.189