Answer:
its B
Step-by-step explanation:
10 students averaged 80, so the sum of their scores was (10 x 80) = 800
20 students averaged 89, so the sum of their scores was (20 x 89) = 1,780
All together, the sum of all 30 scores was (800 + 1,780) = 2,580
30 students totaled 2,580, so their average was (2,580 / 30) = <em> 86</em> .
(40 * 25) + 0.10x = (40 * 20) + 0.20x
1000 + 0.10x = 800 + 0.20x
1000 - 800 = 0.20x - 0.10x
200 = 0.10x
200/0.10 = x
2000 = x <=== weekly sales must be $ 2000
X=skirt
y=sweater
z=shoes
x+y+z=165
y=8/7x
z=x+11
plug it in
x+(8/7x)+(x+11)=165
2x+8/7x=154
22/7x=154
x=49
y=56
z=60
a skirt cost $49, a sweater cost $56, and a pair of shoes cost $60
