A restaurant serves sandwiches and salads. They sold 7 sandwiches and 7 salads for a total of $140 for lunch. In the evening, 21 sandwiches and 77 salads were sold for a total of $700. Let w represent the cost of a sandwich and d represent the cost of a salad.

Part A
Write and equation that represents the total cost at lunch time:
Write an equation that represents the total cost in the evening:

Part B
Find the cost of each sandwich (w ) using your system of equations above:

A) 7w + 7d = 140

21w + 77d = 700

B) $15

Step-by-step explanation:

7w + 7d = 140

w + d = 20

d = 20 - w

21w + 77d = 700

3w + 11d = 100

3w + 11(20 - w) = 100

3w + 220 - 11w = 100

120 = 8w

w = 15

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step-by-step explanation:

the multiples of 15 are 15, 30,45, 60, 75, 90, 105, 120, 135, 150, 165, 180, 195,   210, 225, 240, 255, 270, 285, 300, 315, 330, 345, 360, 375,   390, 405, 420, 435, 450, 465, 480, 495, 510, 525, 540, 555, 570, 585, 600, 615, 630, 645, 660, 675, 690, 705, 720, and 735.

the factors of 15 are 1, 3, 5, and 15.

hope that , fam!

-une, your fren : )