Answer:
4/7
Step-by-step explanation:
1/4 divided by 7/16 is the same thing as 1/4 * 16/7. Multiply this and you will get the fraction of 16/28. Once simplified, this comes out to be 4/7.
Assuming they all contribute the same amount, then each would need to give $2.09, while one would have to give $2.10
Answer:
1. 
2. 
3. 
Step-by-step explanation:

![\bf \textit{exponential form of a logarithm} \\\\ \log_a(b)=y \qquad \implies \qquad a^y= b \\\\[-0.35em] ~\dotfill\\\\ \log(x) = 6.4\implies \log_{10}(x)=6.4\implies 10^{6.4}=x\implies 2511886.43\approx x](https://tex.z-dn.net/?f=%5Cbf%20%5Ctextit%7Bexponential%20form%20of%20a%20logarithm%7D%20%5C%5C%5C%5C%20%5Clog_a%28b%29%3Dy%20%5Cqquad%20%5Cimplies%20%5Cqquad%20a%5Ey%3D%20b%20%5C%5C%5C%5C%5B-0.35em%5D%20~%5Cdotfill%5C%5C%5C%5C%20%5Clog%28x%29%20%3D%206.4%5Cimplies%20%5Clog_%7B10%7D%28x%29%3D6.4%5Cimplies%2010%5E%7B6.4%7D%3Dx%5Cimplies%202511886.43%5Capprox%20x)
let's recall that when the base is omitted, "10" is implied.