Question

a jar contains n nickels and d dimes. there are 24 coins in the jar, and the total value of the coins is $1.70. how many nickels and how many dimes are in the jar

Answer 1

Here's what we know:n + d = 20 (there are a total of 20 nickels and dimes).05n + .1d = 1.4 (total change equals $1.40) There are a couple of ways to solve this. You can go the elimination method by multiplying the second equation by an amount to get rid of a variable, or we can go substitution by isolating a variable in the first equation. I'll go with elimination in this case: -10(.05n + .1d = 1.4) this will cause the d-variable to equal 0: n  +  d = 20-.5n - d = -14------------------.5n = 6n = 12 Now that we know n, we can solve for d:12 + d = 20d = 8 Check:.05 * 12 + .1 + 8 = 1.4.6 + .8 = 1.41.4 = 1.4