A person's heart beats approximately 10^5 times each day. A person lives for approximately 81 years.
(a) Work out an estimate for the number of times a person's heart beats in their lifetime
Give your answer in standard form correct to 2 significant figures.​

The question is kind of confusing. if it's asking how many variations of answers can you give. then do 4^5 for your answer.this would be something like the first question could be a and the 2nd c or first b next c etc. if you can, ask the teacher for a better confirmation of what it's asking. if i'm assuming correctly what it's asking, it's 625 different variations.