Joanna has a total of 50 coins in her purse. • The coins are either nickels or quarters.
• The total value of the coins is $4.35.
Which system of equations can be used to determine the number of nickels, n, and quarters,
q, that Joanna has in her purse?
0.05n + 0.25q = 4.35
50n + 50q= 4.35
On +9= 4.35
50n + 50q = 4.35
On+q=50
0.05n +0.259 = 4.35
0.05n +0.25 = 50
n +9= 4.35

not only in mathematics, scientific proof also are required in the other field of science. also maths proofs are of particular structure, containing steps and logics. so proving is like doing science, it is science. that's why it is important to prove. 

an inaccurate proof leads to errors, or stating results that are not accurate.  which wil mess the probelm up you dont want this

the correct answers i think are b. and d.

give me brainliest if it is correct!