We do not clean natural ponds or lakes, whereas an aquarium or a swimming pool needs to be cleaned regularly. Why?
Read the passage given below and answer the question.
Food chains ‘P’ and ‘Q’ form an interconnection. ‘P’ initiates with wheat grass whose population supports a few grasshoppers, frogs and snakes.
‘Q’ starts with dead decaying leaves of wheat grass which are eaten by earthworms and then food chain is continued with frog of food chain ‘P’.
Identify the types of food chains ‘P’ and ‘Q’:
Four students of class XII are given a problem to solve independently. Their respective chances of solving the problem are: \[ \frac{1}{2},\quad \frac{1}{3},\quad \frac{2}{3},\quad \frac{1}{5} \] Find the probability that at most one of them will solve the problem.