Ms. Muir decided to make trail mix for her next excursion to collect rocks. Dried fruit cost $6.00 per pound and the granola cost $5.50 per pound. She spent $53.75 on 9.5 pounds of trail mix. How many how many pounds of fruit, and how many pounds of granola did she buy?

Number of pounds of dried fruit = 3 pounds

y = number of pounds of granola

= 6.50

Step-by-step explanation:

Dried fruit cost = $6.00 per pound

Granola cost $5.50 per pound

9.5 pounds of trail mix = $53.75

Let

x =number of pounds of dried fruit

y = number of pounds of granola

x + y = 9.5 (1)

6x + 5.50y = 53.75 (2)

From (1)

x = 9.5 - y

Substitute x = 9.5 - y into

6x + 5.50y = 53.75

6(9.5 - y) + 5.50y = 53.75

57 - 6y + 5.50y = 53.75

57 -0.50y = 53.75

-0.50y = 53.75 - 57

-0.50y = -3.25

y = -3.25 / -0.50

= 6.50

y = 6.50 pounds

Substitute y = $6.50 into

x + y = 9.5

x + 6.50 = 9.5

x = 9.5 - 6.50

= 3

x = 3 pounds

Number of pounds of dried fruit = 3 pounds

y = number of pounds of granola

= 6.50

good luck on your studies! : )

david edward.

part a

answer: a reasonable domain is where n is a real number. so n can be between 0 and 10. both endpoints are included.

work shown:

n is the number of days after the experiment starts. the smallest n can be is n = 0 which means that 0 days have gone by, and we're at the start. to find out how large n should be, then replace f(n) with 16.13 and solve for n. use logarithms to isolate the exponent.

f(n) = 12*(1.03)^n

16.13 = 12*(1.03)^n

16.13/12 = (1.03)^n

1.34416666666667 = (1.03)^n

(1.03)^n = 1.34416666666667

log[ (1.03)^n ] = log[ 1.34416666666667 ]

n*log[ 1.03 ] = log[ 1.34416666666667 ]

n = log[ 1.34416666666667 ]/log[ 1.03 ]

n = 10.0062999823929

this rounds to n = 10 which is fairly close but not 100% perfect. so this is the largest n can be.

note: if you plug n = 10 into f(n), you'll get roughly 16.127 which rounds to 16.13 (this comes up again in part c)

=====================================

part b

answer: the y intercept is 12. it represents the starting height of the plant in cm.

work shown:

plug n = 0 into the f(n) function. simplify

f(n) = 12*(1.03)^n

f(0) = 12*(1.03)^0

f(0) = 12*(1)

f(0) = 12

on day n = 0, aka the starting point, the height f(n) is 12 cm

=====================================

part c

answer: the average rate of change is approximately 0.43061036458991 (round however you need to). this represents the average growth rate from day n = 3 to day n = 10. so the plant grew roughly 0.43 cm per day during this timespan, assuming you round to 2 decimal places.

work shown:

compute f(3)

f(n) = 12*(1.03)^n

f(3) = 12*(1.03)^3

f(3) = 13.112724 < we'll use this later

compute f(10)

f(n) = 12*(1.03)^n

f(10) = 12*(1.03)^10

f(10) = 16.1269965521294 < we'll use this later

now use the formula below with a = 3 and b = 10

aroc = average rate of change

aroc = [ f(b) - f(a) ]/[ b - a ]

aroc = [ f(10) - f(3) ]/[ 10 - 3 ]

aroc = (16.1269965521294 - 13.112724)/(10 - 3)

aroc = 3.0142725521294/7

aroc = 0.43061036458991

round this however you need to

note: the plant grew approximately 3.01 cm over 7 days, so roughly 0.43 cm per day is the average growth rate (if you were to round to 2 decimal places).