answer:Let's analyze the information given in the problem.The first piece of information is that 40% of the students prefer pizza and soccer.To find the number of students who prefer pizza and soccer, we calculate 40% of 40.This is 40 * 40 / 100 = 1600 / 100 = 16 students.The second piece of information is that 15% of the students prefer pizza and basketball.To find the number of students who prefer pizza and basketball, we calculate 15% of 40.This is 40 * 15 / 100 = 600 / 100 = 6 students.Now we can calculate the total number of students who prefer pizza.Since pizza is the common preference for these two groups of students, we can add the two groups together to get the total number of students who prefer pizza.This is 16 + 6 = 22 students.So, the total number of students in the cafeteria who prefer pizza over burgers is boxed{22}.

answer:The dining room table was originally priced at 450.A 15% discount amounts to 450 * 15 / 100 = 6750 / 100 = 67.5.So the discount reduces the price of the table to 450 - 67.50 = 382.50.Maria paid an additional 8% sales tax on this amount. The tax amount is 382.50 * 8 / 100 = 3060 / 100 = 30.6.So Maria paid a total of 382.50 + 30.60 = 413.10.Thus, Maria paid a total of boxed{413.10} dollars.

answer:Let's first calculate the effective speed of Mark when cycling uphill against the wind.Since the wind blows at 3 miles per hour against him, his effective speed is reduced to 15 - 3 = 12 miles per hour.The time it takes to cycle up the hill can be calculated by dividing the length of the hill by the effective speed.Time = Distance / Speed = 20 miles / 12 miles per hour.Time = 5/3 hours = 1.67 hours.Thus, it will take Mark boxed{1.67} hours to cycle up the hill.

answer:Let's compute the total amount of money Jackson spent.Each box has 16 packs of pens and he needs to buy 8 boxes, so he needs to buy 8 * 16 = 128 packs of pens.Each pack has 50 pens, so in total he will buy 128 * 50 = 6400 pens.Each pen costs 10 cents which is 0.1.So the total amount he spent is 6400 * 0.1 = 640 dollars.Thus, Jackson spent boxed{640} dollars.

answer:Let's break down the problem:Emily uses 8 pink flowers and 3 times as many yellow flowers as pink flowers. So, the number of yellow flowers is 3 * 8 = 24.The total number of pink and yellow flowers combined is 8 + 24 = 32.She adds the same number of purple flowers as the total of pink and yellow flowers combined, so she uses 32 purple flowers.The total number of flowers used so far is 8 + 24 + 32 = 32 + 32 = 64However, Emily has a total of 60 flowers. This means she has 64 - 60 = 4 flowers less than what she needs.But we need to find out how many lavender flowers she uses. Since the total number of flowers she can use is 60, and she has already used 64 - 4 flowers, the number of flowers that are not lavender is 64 - 4 = 60 - 4 (lavender) flowers.This implies that the number of lavender flowers is 4 flowers less than the total number of flowers, i.e. 60 - 64 = -4 flowers less than 60, i.e. 60 - (64 - 60) flowers = 60 - 4 flowers.However, we need to compute 60 - ( pink + yellow + purple flowers). Since the total number of flowers that are not lavender is 64, and Emily has a total of 60 flowers, we need to subtract 4 flowers from the flowers that are not lavender to get 60 flowers in total.Since there are 8 + 24 + 32 = 32 + 32 = 64 flowers in the garland without the lavender flowers, and we need a total of 60 flowers, this implies that we need to subtract 4 flowers from 64 flowers. However, the question states that we can only have 60 flowers in total, this means we are limited by the number of flowers we can use in total.As we cannot have more than 60 flowers in total, we need to subtract 4 flowers from the 64 flowers to get a total of 60 flowers, i.e. 64 - 4 flowers. This 4 flowers we subtract from the non-lavender flowers (that are 64 in total) are the excess over 60. Since we need a total of 60 flowers and we can only get that by subtracting 4 from 64, i.e. the total number of non-lavender flowers.Thus, we need to subtract these 4 excess flowers over 60 from 64 flowers that are not lavender to get the 60 total flowers that include lavender flowers.Since the total number of flowers we are allowed to use is 60, and the non-lavender flowers are 64 in total, it means we need to use 4 less flowers than the total non-lavender flowers, but this also means that lavender flowers must make up these 4 flowers we need to subtract from the non-lavender flowers to get a total of 60 flowers.So, we subtract these 4 flowers from the non-lavender flowers and use them as lavender flowers instead. Thus, the number of lavender flowers Emily uses is boxed{4}.

answer:Since Emily's piano is missing 1/4 of the white keys, the number of missing white keys is 1/4 * 52 = 0.25 * 52 = 13In addition to the white keys, 5 black keys are also missing.Thus, the total number of keys missing is 13 + 5 = 18.So Emily's piano is missing boxed{18} keys.