I read this story last year for my 7th grade year. The correct answer is A!
Answer:
Do you have the math exercices? I am sorry but I can just help in the subjects concerning math. It is been some time since I studied biology and other high-school subjects.
Answer:
The answer is below
Step-by-step explanation:
Let x represent the cost of 1 scoop of ice cream. Since the cost of 2 scoops of ice cream are twice the price of 1 scoop of ice cream, therefore the cost of 2 scoops of ice cream = 2x
Jean buys 4 tubs with 2 scoops in them and 2 tubs with 1 scoop each. Therefore the money spent by Jean is:
Money spent by Jean = 4(2x) + 2(x) = 8x + 2x = 10x
Sarah buys 2 tubs of 2 scoops and 4 tubs of 1 scoop. The money spent by Sarah is:
Money spent by Sarah = 2(2x) + 4(x) = 4x + 4x = 8x
Sarah spends 2.50 € less than Jean. Therefore:
Money spent by Sarah = Money spent by Jean - 2.5
8x = 10x - 2.5
2x = 2.5
x = €1.25
Therefore the cost of 1 scoop of ice cream is €1.25, the cost of 2 scoops of ice cream is €2.50.
Money spent by Jean = 10x = 10(1.25) = €12.5
Money spent by Sarah = 8x = 8(1.25) = €10
Answer:
x = 50*e∧ -t/100
Step-by-step explanation:
We assume:
1.-That the volume of mixing is always constant 300 gallons
2.-The mixing is instantaneous
Δ(x)t = Amount in - Amount out
Amount = rate * concentration*Δt
Amount in = 3 gallons/ min * 0 = 0
Amount out = 3 gallons/min * x/ 300*Δt
Then
Δ(x)t/Δt = - 3*x/300 Δt⇒0 lim Δ(x)t/Δt = dx/dt
dx/dt = - x/100
dx/ x = - dt/100
A linear first degree differential equation
∫ dx/x = ∫ - dt/100
Ln x = - t/100 + C
initial conditions to determine C
t= 0 x = 50 pounds
Ln (50) = 0/100 * C
C = ln (50)
Then final solution is:
Ln x = - t/100 + Ln(50) or
e∧ Lnx = e ∧ ( -t/100 + Ln(50))
x = e∧ ( -t/100) * e∧Ln(50)
x = e∧ ( -t/100) * 50
x = 50*e∧ -t/100