# How to calculate the failure rate of a machine with probability and mean failure time?

I dont know how to approach this problem. Suppose that a machine has a probability of failure of 43% at 90 hours of operation. How can you calculate the failure rate and the probability of surviving x hours without having failures?

\large{R(t)=e^{\lambda t}}\\ \begin{align} R&=\text{Reliability}\\ t&=\text{time}\\ \lambda&=\text{failure rate} \end{align}
At $$t=0$$
$$R(t=0)=1\\ \implies100\%$$
I think, if the reliability follows exponential distribution, you can use the formula given above. Reliability is the probability that a machine will function normally during a period of time under proper working conditions. So, $$\text{reliability}=1-\text{probability of failure}$$