I am asked to find the number of proposals to submit such that at least one proposal is approved with at least $99\%$ probability.
I have found that the probability of at least one proposal being approved when three proposals are submitted is $0.957125$. It is also provided to me in the question that any one proposal has an approval probability of $0.65$.
Now, what I tried to do to find the minimum number of proposals to achieve at least a $99\%$ success, is by using the standard normal distribution.
I did: $P(Z\ge1)\ge0.99$, $P(Z=0)=0.01$ and $\operatorname{norminv}(0.01, 0, 1) = -2.3263$.
I adopted the standard normal as I was not given any mean or standard deviation in the question. I then realised that calculating the norminv led me nowhere, because I had no mean or standard deviation.
I appreciate any help.