Question

Mates recorded that water levels in one part of river fell 1.05 millimeters per year for 2.48 years. Describe how you could estimate the total variation in water level

Answer 1

The decrease of the decimal rate -1.05 mm/year can be rounded to -1. You don’t need to round 2.48 because you’re multiplying by -1. Since -1.05 is negative and rounded to a greater value, the estimate could be adjusted to a slightly lesser value, maybe -2.5 or -2.6.

Explanation:

Answer 2

2.60 mm drop or -2.60 mm from zero

Explanation:

Level in the river continues dropping at an average rate of 1.05 mm/year

So total variation is the total drop over the period of 2.48 years and is:

• 1.05 mm/year * 2.48 year = 2.60 mm

So total variation is 2.60 mm drop or -2.60 mm from zero level