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Algebra_4
Chapter 90
Problem 4
Select a different problem
Example:
Use the process of elimination to solve the following:
Given:
There are a total of 5 nickels and dimes in a bag.
When added up, they amount to 40 cents total.
How many nickels, N
N and dimes N
D, are in the bag?
These facts can be written in shorthand form as:
(1) 5N
N + 10N
D = 40 = total cents
and
(2) N
N + N
D = 5 = total number of coins
Multiply equation (2) by -5 and add it to equation (1).
This gives:
5N
N + 10N
D = 40
-5N
N - 5N
D = -25
--------------------------------------
5N
D = 15
(3) or N
D = 3 = (number of dimes)
Substituting equation (3) back into equation (2) gives
N
N + N
D = N
N + 3 = 5
(4) or N
N = 2 = (number of nickels)
