Algebra 1 Common Core Student Edition, Grade 8-9

Q Apply 37. Statistics Approxim ately 3 p eople out of every 30 are left-handed. A bout how

m any left-handed people w ould you expect in a group of 140 people?

3 8. T h in k A b o u t a P lan Maya ru n s 100 m in 13.4 s. Amy can ru n 100 m in 14.1 s. If Amy

were to finish a 100-m race at the sam e tim e as Maya, how m uch of a h e a d start, in

m eters, w ould Amy need?

• W hat inform ation do you know? W hat inform ation is unknow n?


• W hat pro p o rtio n can you write th a t will help you solve the problem?

39. Electricity The electric bill for F erguson’s F urniture is show n at the
    right. The cost of electricity p e r kilow att-hour an d th e total charges
    for one m o n th are given. How m any kilow att-hours of electricity
    did F erguson’s Furniture use in th a t m onth?


40. Video Downloads A p articular co m p u ter takes 15 m in to
    dow nload a 45-m in TV show. How long will it take th e co m p u ter to
    dow nload a 2 -h movie?

<$> C e n t e r v i l l e E l e c t r i c

Account Name: Ferguson's Furniture

Account Number: [34-14567-891

Cost per kilowatt-hour $.07

Total charges $143.32

Previous balance $.00

T o t a l A m o u n t D u e [ $ 1 4 3 .3 2 [

41. Schedules You w ant to m eet your friend at a p ark 4 m i away from
    your house. You are going to bike to the p ark at an average rate of 10 m i/h. Your
    friend lives 1.2 mi away from th e park an d walks at an average rate of 3 m i/h. How
    m any m inutes ah ead of you should your friend start o u t so th a t you m eet at the
    p ark at th e sam e time?

Solve each proportion. Tell whether you used the Multiplication Property of

Equality or the Cross Products Property for your first step. Explain your choice.

42.

45.

48.

P = 7

4 8

_r_ _ 315

2.1 2.8

b + 13 = -5 b

2 3

43 —4.5

46.

49.

2

5

JL = i

14 n

3b _ 3

b-4 7

44.

47.

50.

3_ = b

10 7

L5 _ 225

y 7

x + 2 _ 3

2x — 6 8

51. Error Analysis D escribe an d correct th e error in solving th e p ro p o rtio n
    at the right.


52. Bakery A bakery sells packages of 10 bagels for $3.69. If th e bakery
    starts selling the bagels in packages of 12 , how m u ch w ould you expect a
    package of 12 to cost?
    (3D $3.08 CX $4.43
    G D $4.32 C X $4.69


53. Open-Ended W rite a pro p o rtio n th a t contains a variable. N am e th e extrem es, the
    m eans, an d the cross products. Solve the proportion. Tell w h e th e r you u sed the
    M ultiplication Property of Equality or the Cross P roducts P roperty to solve the
    proportion. Explain your choice.

{•jjjKJ} 5 4. B io lo g y M any trees have concentric rings th a t can be co u n ted to d eterm in e the

tree's age. Each ring represents one year's growth. A m aple tree with a d iam eter of

12 in. has 32 rings. If th e tree continues to grow at a b o u t th e sam e rate, how m any

rings will th e tree have w h en its d iam eter is 20 in.?

\ 8 _ x + 3 /

2 /

3

13 ^

x X

128 Ch ap t er 2 So l v i n g Eq u a t i o n s