Point of intersection Question: Mike has $9.85 in dimes and quarters. If there are 58 coins altogether,
how many dimes and how many quarters does Mike have? Use the point of intersection to find the answer. Explain how you used a formula to calculate the # of quarters and dimes

Answers:

He has  27   quarters and  31   dimes

Work Shown:

d = number of dimes

q = number of quarters

d+q = 58 since there are 58 coins of only these two types

d = 58-q

10d+25q = 985 note that 985 cents is $9.85

10(58-q)+25q = 985 replace d with 58-q

580-10q+25q = 985

15q+580 = 985

15q = 985-580

15q = 405

q = 405/15

q = 27 Mike has 27 quarters

d = 58-q

d = 58-27

d = 31 Mike also has 31 dimes

As a way to check:

d+q = 31+27 = 58 so that works out

and

10d+25q = 10*31+25*27 = 310+675 = 985

so that works out as well. The answer is confirmed.

c

step-by-step explanation: