Bell Work:
What is the volume of 2 liters of
water?
Answer:
2000 cm
3
Lesson 105:
Compound Average and
Rate Problems
In this lesson we will solve
problems that include more than
one average or rate.
Example:
Blanca bought 200 shares of XYZ
stock at an average price of $54
per share. Later she bought 100
more shares at $60 per share.
What was the average price per
share Blanca paid for all 300
shares of XYZ?
Answer:
200 shares at $54 = $10,800
+100 shares at $60 = $6,000
300 shares at x = $16,800
x = $56
Example:
After three games of bowling,
Gabe’s average score was 88.
what score does Gabe need to
average in his next two games to
raise his average to 90?
Answer:
3 x 88 = 264
5 x 90 = 450
450 – 264 = 186
186/ 2 = 93
93 on his next two games.
Many rate problems can be solved
like average problems as we see
in the next example.
Example:
Because of the heavy traffic, the 120mile trip to San Diego took 3 hours.
The traffic was lighter on the return
trip, which took 2 hours. Find the
average speed for each trip and for
the round trip.
Answer:
120miles/3hours = 40mph
120miles/2hours = 60mph
120 + 120/3 + 2 =
240miles/5hours 48mph
HW: Lesson 105 #1-25