0.8p - 50 < = 150
0.8p < = 150 + 50
0.8p < = 200
p < = 200/0.8
p < = 250
the reason I set it up this way is because when it is 20% off, u r actually paying 80% of the original price (p)....80% of the original price is written as 0.8p...then u subtract ur 50 dollar discount coupon...- 50.....and if all she can spend is 150....it would be less then or equal to 150. So the most she can spend on the phone is 250
Answer:
50%: day 13
100%: day 26
Step-by-step explanation:
We are given two days and the amount of the moon that is illuminated. The two days are points on a straight line.
(1, 0.02), (2, 0.06)
y = mx + b
m = (0.06 - 0.02)/(2 - 1) = 0.04
y = 0.04x + b
0.02 = 0.04(1) + b
b = -0.02
y = 0.04x - 0.02
We want y = 50% = 0.5
0.04x - 0.02 = 0.5
0.04x = 0.52
x = 13
y = 100% = 1
0.04x - 0.02 = 1
0.04x = 1.02
x = 25.5
The answer to this is x < -10/7
