Ajar contains n nickels and d dimes there are 20 coins in the jar, and the total value of the coin s is one dollar and forty cents. how many nickels and how many dimes are in the jar?

A) n + d = 20
B) .05n + .10d = 1.40 Multiplying A) by -.10
A) -.1n  -.1d = -2      Then adding it to B
B) .05n + .10d = 1.40
-.05n = -.60
n = 12 nickels
d = 8 dimes

In all honesty, there really is no “work” per say to show. mainly it’s just using the process of elimination. the question is asking which domain(s) would be the most appropriate for the function c(n). n is the number of observed vehicles so right away, 1, 2, and 3 can be eliminated.why? 1, 2 start in the negatives and therefore it is impossible to observe negative cars. so, #4 would be the best answer to the given problem.