AVERAGES &PERCENTAGESMaria Nguyen

Danny Jacobs

AVERAGES

A calculated “central” value of a set of numbers.

Sum of a list of numbers divided by the size of the list.

Can be used to refer to the median and mode

Also known as the mean

EXERCISE 6

John drove for three hours at a rate of 50 miles per hour

and two hours at 60 miles per hour. What is the average

speed for the whole journey? (hint Distance= Rate x Time)

3 hrs @ 50 mph 3 ⋅50=150miles

2 hrs @ 60 mph 2 ⋅60=120miles

total miles 120+150=270miles

total hours 3+2=5 hours

entire trip270miles5hours

=54miles per hour¿ ( total milestotalhours )AVERAGES

EXERCISE 8

The average age of Mr. and Mrs. Smith four years ago was

28 years. If the current average age of Mr. and Mrs. Smith

and their son is 22 years, what is the age of their son?

AVERAGES

4 yrs ago today

A = Mrs. SmithB = Mr. SmithC = Son

ages today

AVERAGES

EXERCISE 8

-64 -64

PERCENTAGES

What does percentage mean?

PER

CENTthrough or for every hundred

20100

⋅ $80

Example: 20 percent of 80 dollars

¿$16

PERCENTAGES

How are percentages used?

PERCENTAGES

EXERCISE 4

In a basketball tournament, Sally took 20 shots and scored

on 55% of them. After she took 5 more shots, she raised

her percentage to 56%. How many of the last 5 shots did

she make?

25 shots

last 5 shots

20 shots shots made

shots made

PERCENTAGES

EXERCISE 15Miki has a dozen oranges of the same size and a dozen

pears of the same size. Miki can extract 8 oz. of pear juice

from 3 pears and 8 oz. of orange juice from 2 oranges. She

makes a pear-orange juice blend from an equal number of

pears and oranges. What percent of the blend is pear juice?

6 pears 6 oranges

3 pears=8oz

38=6𝑥

𝑥=16 oz

2oranges=8oz

28=6𝑥

𝑥=24 oz

6 pears = 16 oz 6 oranges = 24 oz

percent pear juice

t otal juice=16+24

¿ 40oz

16 ( pear juice )40( total juice)

= 410

=40%