Let's call the 13¢ stamps a and the 18¢ stamps b:
a+b = 42 and therefore a= 42-b (formula 1)
0.13a+0.18b= 6.66 In this formula, substitute the value of a according to formula 1:
0.13(42-b)+0.18b= 6.66 Multiply on the left to get rid of the parenthesis:
5.46-0.13b+0.18b= 6.66 Subtract 5.46 from both sides:
-0.13b+0.18b= 1.20 Add on the left:
0.05b= 1.20 Divide both sides by 0.05
b= 24 You have 24 18¢ stamps and:
42-24= 18 13¢ stamps
Check: (24 x 0.18) + (18 x 0.13)= 6.66 Correct.
Answer:
x=21−7y?
Step-by-step explanation:
I don't really know what else to do
Answer:
25%
Step-by-step explanation:
Let v, t be the current average speed and the time taken to reach the school respectively.
As distance = speed x time, so,
distance, d=vt...(i)
Let V be the new average speed in order to to take 20% less time than t.
So, time taken with speed V = t-20% of t = t- 0.2t= 0.8t
As distance is constant, so
d= V(0.8t)= 0.8Vt
hBy using equation (i), we have
0.8Vt = vt
0.8 V = v
V= v/0.8=1.25v
Therefore, the percentage increase in the average speed = 
=25%
Hence, the percentage increase in the average speed is 25%.
Answer:
Sea level
Step-by-step explanation:
In geography, 'Elevation' is measured in relation to sea level, so sea level would be zero.
Thus, Chicago is 600 feet above sea level and Seely, California is 200 feet below sea level.
If there were nothing but flat land all the way from Seely to the ocean, sea water would come in and cover Seely. Fortunately for the people in Seely. California's coastal mountain range is between the town and the ocean, so that does not happen.
If you want it simplified -6k+5, if you need the answer lmk
