<span>You need to set up 2 equations for this, a system to be exact
let x represent the cheaper phone and y represent the upgraded phone
for store costs you will have
5x+25y=200
for selling prices you will have 30x+100y=900
set these two equations together
5x+25y=200
30x+100y=900
multiply the first one by -4 and add them
-20x-100y=-800
30x+100y=900
10x=100
x=10
10 cheaper phones, plug into any equation again
5(10)+25(y)=200
y=6<<<6 upgraded phones</span>
Answer:
75.5 cm
Step-by-step explanation:
S = (a+b)*h/2
h = 2 * S / (a+b) = 2 * 7701 / 204 = 75.5 cm
I'm not sure, but the average time can be 1/250 seconds.
The number is 500. 500×7=3,500.
