She needs to score a 91 on her next test because 85+78+77+69+91=400 and 400 divided by 5 gives you a mean of 80.
Answer:
9/10 is 90%
Step-by-step explanation:
You just make it a percentage
Let x = # of 25-cent stamps
y = # of 2-cent stamps
{ x+ y = 88
{ 0.25x + 0.02y = 15.56
60 25-cent stamps 28 2-cent stamps
By looking at the graph and seeing which point crosses the y axis. This point will always have an x coordinate of zero.
