Tutor profile: Yashjit G.

If two typists can type two pages in two minutes, how many typists will it take to type 18 pages in six minutes?

Since two typists can type two pages in two minutes, then one typist can type two pages in four minutes, which means that the rate of one typist is: rate = job/time = 2/4 = 1/2 pages per minute Now, (combined rate of x typists)*(time)=(job) --> (1/2∗x)∗6 = 18 x = 6

Is it ideally possible to stop "ageing"?

Ideally? Yes! There are these entities in your chromatin network known as "telomeres" which influence a cell to divide and reduce in numbers with each division. So, ideally speaking, if we can maintain the number of telomeres within each cell then it'll be possible to stop, or even reverse ageing. However, in real case scenarios, a high number of telomere is associated with cancer as it leads to uncontrolled division of the cell!

When can calculus be considered "exact" and when can it be considered as an "approximate"?

Generally speaking, within the field of mathematics, even if we are considering the limit of a variable tending to infinity (an approximate value), the nature of calculus is always "exact" unless otherwise mentioned. However, when applied to real-life problems, the same becomes an "approximate" because physical systems are complex with unaccounted variables.