Question

A number, a, rounded to 1 d.p. is 25.3

Another number, b, rounded to 1 d.p. is 3.3
Work out the upper bound of a/b to 1 d.p.

Answer 1

25.25 ≤ a < 25.35

3.25 ≤ b < 3.35

1/3.35 < 1/b ≤ 1/3.25

25.25/3.35 < a/b < 25.35/3.25

7.5 < a/b < 7.8

The upper bound of a/b is 7.8.