a) Martha's thought is incorrect
b) Renne will pay $340 , Susan will pay $297.50 while Martha will pay $202.50
a) Here, we want to know if Martha's throught is right
Renne is paying 40%
Susan is paying 0.35
Mathematically;
![0.35\text{ = }(35)/(100)\text{ which is 35\%}](https://img.qammunity.org/2023/formulas/mathematics/college/zv995k362mez1icwfdp24sekubuqbtdqzi.png)
So, what is left to pay is;
![100-35-40\text{ = 25\%}](https://img.qammunity.org/2023/formulas/mathematics/college/tm3urfdk8jm7n1kys40oe92fycvr5klogv.png)
Now, to know if Martha is correct, we need to check or evaluate if 25% is same as 1/3
Mathematically;
![\begin{gathered} 25\text{ percent = }(25)/(100)\text{ = }(1)/(4) \\ \\ (1)/(4)\\e\text{ }(1)/(3) \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/5dfxdix20pxq7brrdu04vlrf7yoks478on.png)
Since both fractions are not equal, we can conclude that Martha is incorrect
b) Here, we want to know how much each individual will pay given the total cost
Renne paying 40%;
![R\text{ = }(40)/(100)*850\text{ = 340}](https://img.qammunity.org/2023/formulas/mathematics/college/4258dlyr11hg5gwhe5ijb23jx4kmfrs25t.png)
Susan payin 0.35;
![S=\text{ 0.35}*850\text{ = \$297.50}](https://img.qammunity.org/2023/formulas/mathematics/college/cxbtwec2qirk3ldznmkrpxemx63narr19h.png)
Martha paying the remainder;
![M\text{ = 840-340-297.5 = \$202.50}](https://img.qammunity.org/2023/formulas/mathematics/college/dplw288m1dv4v3hockfwaxvmcvvum5hc3p.png)