Question

Iliana and Rod were asked to find the difference of (5.1 times 10 Superscript negative 15 Baseline) minus (2.3 times 10 Superscript negative 14 Baseline). As a first step, Iliana rewrote the problem as (0.51 times 10 Superscript negative 14 Baseline) minus (2.3 times 10 Superscript negative 14), and Rod rewrote the problem as (5.1 times 10 Superscript negative 15 Baseline) minus (0.23 times 10 Superscript negative 15 Baseline). Which person wrote a correct possible first step? Why?

Answer 1

B "Only Iliana is correct because Rod incorrectly equated 2.3 times 10 Superscript negative 14 and 0.23 times 10 Superscript negative 15."

Step-by-step explanation:

Answer 2

Given:

The expression is

`(5.1* 10^(-15))-(2.3* 10^(-14))`

First steps of Iliana and Rod are given.

To find:

Which person wrote a correct possible first step.

Solution:

We have,

`(5.1* 10^(-15))-(2.3* 10^(-14))`

If we want -15 in the power of 10, then

`(5.1* 10^(-15))-(2.3* 10^(-14-1+1))`

`(5.1* 10^(-15))-(2.3* 10^(-15)* 10)`

`(5.1* 10^(-15))-(23* 10^(-15))`

Therefore, first step of Rod is incorrect.

If we want -15 in the power of 10, then

`(5.1* 10^(-15+1-1))-(2.3* 10^(-14))`

`(5.1* 10^(-14)* 10^(-1))-(2.3* 10^(-14))`

`((5.1)/(10)* 10^(-14))-(2.3* 10^(-14))`

`(0.51* 10^(-14))-(2.3* 10^(-14))`

Therefore, first step of Iliana is correct.