Question

A length is measured at 21 cm correct to two significant figures, what is the lower bound of the length and upper bound?

Answer 1

20.5 and 21.5

Explanation:

It says 2 significant figures so the least it can possibly be is 0.5 less and the most it can be is 0.5 more as if it was, lets say 20.4 it would round down to 20 not 21.