Question

Rachel and Sam stopped at the donut stop before work. Rachel bought a protein smoothie and 2 boxes of donut holes for $11.65. Sam bought 2 protein smoothies and 1 box of donut holes for $10.55.
Use the substitution method to solve a system of equations relating S, the cost of a smoothie, and D, the cost of a box of donut holes.
S + 2D = 11.65
2S + D = 10.55
How much does each item cost?
Select one:
a. Smoothie $3.70; box of donut holes $3.70
b. Smoothie $4.25; box of donut holes $3.15
c. Smoothie $3.15; box of donut holes $4.25
d. Smoothie $2.95; box of donut holes $4.35

Answer 1

(: shpanks

Answer 2

okay so sub method means we have to first isolate an equation in terms of 1 variable
S+2D=11.65
S=11.65- 2D
Now we sub this into the 2nd equation
2S + D = 10.55
2*(11.65-2D)+D=10.55 <---- we can simplify this and solve for D
23.3-4D+D=10.55
-3D=-12.75
D=12.75/3=4.25

Answer 3

S+2D=11.65
S+2(4.25)=11.65
S=11.65-8.5=3.15