Some friends went hiking for 3.5 hours. They traveled 21 kilometers in that time. Birgit was 4 minutes/km faster than the average time. If Birgit kept the same pace, how many minutes would it take her to go 8 kilometers?
Let's think: Minutes spent hiking = 3.5 * 60 = 210 minutes. Average speed = 210 minutes / 21 km = 10 minutes / km. Birgit is 4 minutes / km faster = 10 - 4 = 6 min / km. It would take 6 * 8 = 48 minutes to go 8 km. Birgit would take 48 minutes to travel 8 kilometers.. The answer is: 48.

Mr. Maximilian is a dairy animal farmer and has 140 cows on his farm. Forty percent of the cows on his farm have a red spot, 25 percent of the cows without a red spot have a blue spot and the remaining cows do not have any spot. How many cows on the farm have no spot?
Let's think: If Mr. Maximilian has 140 cows and 40% of them have red spots, then 40 / 100 * 140 = 56 cows have red spots. The number of cows with no red spot is 140 - 56 = 84 cows. Out of the 84 cows without a red spot, 25% of them have a blue spot, a total of 25 / 100 * 84 = 21 cows. The number of cows without any spot is 84 - 21 = 63 animals.. The answer is: 63.

Linda owns a store. She sells jeans at 11 dollars each and tees at 8 dollars each. If she sold 7 tees and 4 jeans in a day, how much money, in dollars, did she have at the end of the day?
Let's think: 7 tees cost 7 * 8 = 56 dollars. 4 jeans cost 4 * 11 = 44 dollars. Linda had 56 + 44 = 100 dollars in the end.. The answer is: 100.

The teacher divided the students into four groups. One group had 5 students, another 8 students, and the third 7 students. If there were 24 total students, how many students were in the fourth group?
Let's think:
There are 5 + 8 + 7 = 20 students in the first three groups. There are 24 - 20 = 4 students in the fourth group.. The answer is: 4.