Alana has run many marathons and keeps track of all of her finishing times. At a marathon last month, she finished in 290 minutes. The other day, she ran another marathon and finished with a time of 261 minutes. What is the percent of decrease in Alana's marathon time?

the percentage of decrease in Alana's marathon time  is 10%

Step-by-step explanation:

To start we have to know the fraction that represents what ran in the second marathon with respect to the first

to do it we have to divide the second marathon over the first

261/290 = 0.9

if we multiply this by 100 we will obtain the percentage

0.9 * 100 = 90%

if the first marathon was 100% and the second marathon was 90%

100% - 90% = 10%

the percentage of decrease in Alana's marathon time  is 10%

i dont get it. where are the "descriptions"?