question 1- john has nickels quarters and dimes totaling $3.30,21 coins in all,with one more nickel than dimes.How many of each type of coin does he have?

Answer 1

put each clue into symbols

work with the values, and also the numbers of coins:

5n+10d+25q = 330
n+d+q = 21
n = d+1

(n,d,q) = (6,5,10)