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Zorluk: KolaySystems of Linear Equations

A café sells small cold brew coffees for $4\$4 each and large cold brew coffees for $6\$6 each. On Monday morning, the café sold a total of 4040 cold brew coffees for $196\$196. How many large cold brew coffees were sold?

Cevap: 18

Cevap

The café sold 18 large cold brew coffees.
Setting up the system s+l=40s + l = 40 and 4s+6l=1964s + 6l = 196, substituting s=40ls = 40 - l yields 4(40l)+6l=1964(40 - l) + 6l = 196. Simplifying gives 160+2l=196160 + 2l = 196, so 2l=362l = 36 and l=18l = 18.

Adım Adım Çözüm

1
Set up equations based on total count and total cost.
Let ss = number of small coffees and ll = number of large coffees. The system is s+l=40s + l = 40 and 4s+6l=1964s + 6l = 196.
The problem gives two distinct relationships between the quantity sold and the total dollar value.
2
Substitute s=40ls = 40 - l into the second equation.
4(40l)+6l=196    160+2l=1964(40 - l) + 6l = 196 \implies 160 + 2l = 196.
Substituting reduces the system from two variables to a single equation in ll.
3
Solve the linear equation for ll.
2l=36    l=182l = 36 \implies l = 18.
Subtracting 160 from both sides and dividing by 2 yields the number of large cold brews.

Anahtar Kavram

Solving systems of linear equations in two variables using substitution.
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