Answer :
Answer:
3 milkshakes 3 sundaes
Step-by-step explanation:
First write the equation.
y = total cost
x = cost of sundae
z = cost of milkshake
21=2x+5z
x+z=6 or x = 6-z
substitute in x = 6-z into the first equation
21 = 2(6-z) + 5z
21 = 12 - 2z + 5z
21 = 12 + 3z
subtract 12 from both sides
21 - 12 = 12 - 12 + 3z
9 = 3z
divide both sides by 3
3 = z
so she bought 3 milkshakes.
That means x+z = 6 and z=3 so
x+ 3 = 6, then x=3 as well, so she bought 3 sundaes.
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Answer:
she bought 3 sundaes and 3 milkshakes
Step-by-step explanation:
let's call the amount of milkshakes M.
let's call the amount of sundaes S.
you know that in total, there are 6 children.
so, you can make the following equation:
M + S = 6
if the milkshakes cost 5$ each, then the cost of the milkshakes can be expressed as 5m
if the sundaes cost 2$ each, then the cost of the sundaes can be expressed as 2S
you also know that Mrs. Browning spent 21$ in total.
so, you can make the following equation:
5m + 2S = 21
this is a system of equations.
using the first equation, you know that M = 6 - S
you can substitute M for 6 - S in the second equation
5m + 2s = 21
5(6 - s) + 2s = 21
30 - 5s + 2s = 21
30 - 3s = 21
30 = 21 + 3s
30 - 21 = 3s
9 = 3s
3 = s
now that you know how many sundaes there are, you can substitute that into the first equation:
m + s = 6
m + 3 = 6
m = 6 - 3