A farm grew 19.8 tons of wheat in 2013. The farm's wheat output increased by 9.8% from 2013 to 2014 and by 5.1% from 2014 to 2015. Which expression represents a for estimating the total output of wheat, in tons, in 2015? A. 20 + 10 + 5
B. 20(10)(5)
C. 20 + 1.1 + 1.05
D. 20(1.1)(1.05)

Choice D

Explanation:

The increase of 9.8% rounds to 10% when rounding to the nearest ten

An increase of 10% would use the multiplier 1.1

Think of it like saying 1 + 0.10 = 100% + 10%

Similarly, the 5.1% rounds to 5% and an increase of this amount will use the multiplier 1.05

So if we started with 20 items, then 20(1.1)(1.05) is the expression that estimates an increase of 10% followed by an increase of 5%. The order doesn't matter (so you could increase by 5% first, then 10% later).

6e14 is the answer.