Lin runs 5 laps around a track in 8 minutes. If Lin runs 21 laps at the same rate, how long does it take her?
a) 13.13 minutes
b) 441 minutes
c) 33,6 minutes
d) 1.6 minutes

It will take 25.2 minutes to complete 21 laps.

Step-by-step explanation:

The rate of covering 5 laps is:

v = 6/5

Therefore, the time taken to cover 21 laps is:

t = 21/v

t = 21*6/5

t = 25.2

Hence, it will take 25.2 minutes or 25 minutes 12 seconds for Lin to complete 21 laps.  

15

Step-by-step explanation:

If 10 oz. box costs $3.50 and a 16 oz. box costs $5.00 and she collected $97.50 we can represent an expression that relates for how many money Jillian made:

(1)

where x is the number of 10 oz. boxes and y is the number of 16 oz. boxes.

She sold 24 boxes therefore:

(2)

We can right equation in terms of y and substitute it into equation 1:

(2)

Solve for x:

Jillian sold 15 10oz. boxes