Kelsey painted 1/4 of her bedroom in 3/7 of an hour at this rate how long would it take her to paint the entire room

Sum of the interior angles of a pentagon

I'm at a bookstore with $\$35$ in my pocket and a $20\%$-off coupon. what is the cost of the most expensive book i can buy with my money and the coupon? (assume that there are books of every possible price in the bookstore. it's a large bookstore! )

Awoman won a 4000-m race with a time of 12.089 min. what was her rate?