Well here is your first part...

3.56×10^-5

Its negative so go to the left:

=.00000356

Here is your second part...

4×10^4×3×10^4

There both positive so go to the right

=40000 =30000

Then you multiply....

40000×30000=

= 1200000000

Here's your third part...

You need to divide 31 by 117

31÷117=

=0.2650%

7 0

3 years ago

Ana can finish a certain job in 10 hours. Together, Ana and Nina can finish the same job in 3 hours. How many hours can Nina fin

Over [174]

Answer: 4.5 hours

<u>Step-by-step explanation:</u>

$Ana: \dfrac{1}{10}\ \text{job per hour}\\\\Nina: \dfrac{1}{x}\ \text{job per hour}\\\\Together: \dfrac{1}{3}\ \text{job per hour}\\\\\\Ana + Nina = Together\\\dfrac{1}{10}\quad +\dfrac{1}{x}\quad =\quad \dfrac{1}{3}\\\\\\\dfrac{1}{10}(30x)+\dfrac{1}{x}(30x) =\dfrac{1}{3}(30x)\\\\\\\rightarrow\quad 3x+30=10x\\\\.\quad 3x+30=10x\\\underline{-3x\qquad \quad -3x\quad}\\.\qquad \quad 30=7x\\\\.\qquad \quad \dfrac{30}{7}=\dfrac{7x}{7}\\\\\\.\qquad \quad \dfrac{30}{7}=x$