Jennifer went to the post office for stamps. She bought the same number of 8-cent stamps and 10-cent stamps. She also bought as
many 2-cent stamps as both of the other two kinds combined. How many of each kind did she get if she paid a total of $4.40 for them all? Due today! IM SO CONFUSED
Write it out as a set of equation: Let x be number of 8 cent stamps, y be 10 cent stamps, and z be 2 cent stamps. x=y z=x+y 8x+10y+2z=440 Lets first solve for x: from x=y and z=2x(from first equation) the last equation is 8x+10x+4x=440 22x=440 x=20 know that x=20, you also know that y=20 as well, since z=x+y, z=40. So 20 8-cent stamps, 20 10-cent stamps, and 40 2-cent stamps.
X=number of 8-cent stamp=number of 10-cent stamp y=number of 2-cent stamp. $4.40=400 cents
She bought the same number of 8.cent stamp and 10 -cent stamps, she also bought as many 2-cent stamps as both, therefore: x+x=y ⇒2x=y We can suggest this system of equations:
2x=y 8x+10x+2y=440
We can solve this system of equation by substitution method.
