SOLUTION: System of Two Linear Equation : if man has $315 in ten and five dollar bills, how many of each does he have if he has 42 bills in all?
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Question 1024618: System of Two Linear Equation : if man has $315 in ten and five dollar bills, how many of each does he have if he has 42 bills in all? Answer by ikleyn(52781) (Show Source):
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System of Two Linear Equation : if man has $315 in ten and five dollar bills, how many of each does he have if he has 42 bills in all?
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f + t = 42, (1) (f = # of 5-dollar bills)
5f + 10t = 315. (2) (t = # of 10-dollar bills)
Express f = 42-t from (1) and substitute it into (2). You will get a single equation for t
5*(42-t) + 10t = 315.
Simplify and solve it:
210 - 5t + 10t = 315,
5t = 315 - 210,
5t = 105,
t = = 21.
Thus there are 21 of 10-dollar bills.
Then the number of 5-dollar bills is 42-21 = 21.
Check: 5*21 + 10*21 = 105 + 210 = 315. OK.
