Roger purchases two doughnuts and three cookies at a doughnut shop and is charged $3.30. Sam purchases five doughnuts and two cookies at the same shop for $4.95. All the doughnuts have the same price and all the cookies have the same price. Find the cost of one doughnut and find the cost of one cookie.
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If you can
3c + 1d =3.30
2c + 5d = 4.95
Now solve by substitution.
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I'm sorry, but I am unable to visit external websites. However, I can help you solve the problem using substitution.
Let's solve the system of equations:
1. 3c + 1d = 3.30
2. 2c + 5d = 4.95
We can start by solving equation 1 for c:
3c + 1d = 3.30
3c = 3.30 - 1d
c = (3.30 - d)/3
Now we substitute this value of c into equation 2:
2(3.30 - d)/3 + 5d = 4.95
(6.60 - 2d)/3 + 5d = 4.95
Multiply through by 3 to get rid of the fraction:
6.60 - 2d + 15d = 14.85
13d = 8.25
d = 8.25/13
d ≈ 0.6346
Now we substitute the value of d back into equation 1 to find c:
3c + 1(0.6346) = 3.30
3c + 0.6346 = 3.30
3c = 3.30 - 0.6346
3c = 2.6654
c ≈ 0.8885
So, the cost of one doughnut is approximately $0.8885 and the cost of one cookie is approximately $0.6346.