@ Choose a Method Choose paper and pencil, mental math, or a calculator to tell
which measurement is greater.- 640 ft; 0.5 m i 32. 63 in.; 125 cm 33. 75g;5oz
@ 34. Think About a Plan A college stu d en t is considering a subscription to a social-
netw orking In tern et site th a t advertises its cost as "only 87 cents p e r day.’’ W hat is
th e cost of m em b ersh ip in dollars p er year?- How m any conversion factors will you n e e d to u se to solve th e problem?
- How do you choose the ap propriate conversion factors?
- Recipes Recipe A m akes 5 d in n er rolls using 1 c of flour. Recipe B m akes 24 rolls
using l\ c of flour. Recipe C m akes 45 rolls using 10 c of flour. W hich recipe requires
th e m ost flour p er roll?
0 36. Error Analysis F ind th e m istake in th e conversion below. Explain th e m istake an d
convert th e units correctly.
^ 37. Writing Suppose you w ant to convert kilom eters to miles. W hich u n it should be in
th e n u m era to r of th e conversion factor? W hich u n it should b e in th e denom inator?
Explain how you know.
^ 38. Reasoning W ithout perform ing th e conversion, d eterm in e w h e th e r th e n u m b e r of
new units will be greater or less th a n th e n u m b e r of original units.
a. 3 m in 20 s converted to seconds
b. 23 cm converted to inches
c. kilom eters p er h o u r converted to m iles p e r h o u r- Exchange Rates The table below shows som e exchange rates on a p articular
day. If a sw eater sells for $39.95 in U.S. dollars, w hat should its price b e in rupees
and pounds?
@ 40. Estimation Five m i is approxim ately equal to 8 km. Use m ental m ath to estim ate
th e distance in kilom eters to a tow n th a t is 30 m i away.
0 41. Reasoning A ca rp en ter is building an e n te rta in m e n t center. She is calculating the
size of the space to leave for th e television. She w ants to leave ab o u t a foot of space
on eith er side of the television. W ould m easuring th e size of th e television exactly or
estim ating the size to th e n ea rest in ch be m ore appropriate? Explain.120 Chapter 2 So l v i n g Eq u a t i o n s