There are 10 students in a class. The average age of 9 of them is 8 years. By how many years will this average increase if the tenth student is (quite strangely) 28 years old?

How old are the 9 students? ** 9 students have an average age of 8 years so the sum of their ages is 9*8 =

<<9*8=72>>72 years How old will the tenth student be? ** A tenth student who is 28 years old will make the sum 72+28 = 100 years How old will the new average be? ** The new average age will be 100/10 = <<100/10=10>>10 years How many years will the average increase by? ** This is 10-8 = <<10-8=2>>2 years higher than the previous average. #### 2 Jerry takes 2 antacids that weigh 2 grams each and are 5% zinc by weight. Then he takes three more smaller antacids that weigh 1 gram each and have 15% zinc. How many milligrams of zinc does he eat? How many grams are the big antacids? ** First find the total weight of the big antacids: 2 grams/antacid * 2 antacids = <<2*2=4>>4 grams How many milligrams are the big antacacs? ** Then convert that weight to milligrams: 4 grams * 1000 mg/gram = <<4*1000=4000>>4000 mg How much zinc is in the big antacids? ** Then multiply that number by 5% to find how much zinc is in the big antacids: 4000 mg * 5% = <<4000*5*.01=200>>200 mg How many milligrams are the smaller antacids? ** Then find the total weight of the smaller antacids in milligrams: 3 antacids * 1 gram/antacid * 1000 mg/gram = <<3*1*1000=3000>>3000 mg How much zinc is in the small antacids? ** Then multiply that number by the percent of zinc to find the amount of zinc in the small antacids: 3000 mg * 15% = 450 mg How many milligrams of zinc does he eat? ** Then add the zinc Jerry gets from each set of pills to find the total amount of zinc he eats: 450 mg + 200 mg = <<450+200=650>>650 mg #### 650 Tom weighs 150 kg. He manages to hold 1.5 times his weight in each hand while wearing a weight vest weighing half his weight. How much total weight was he moving with? How much weight was Tom carrying in each hand? ** He was carrying 150*1.5=<<150*1.5=225>>225 kg in each hand How much total weight was Tom carrying? ** So he had 225*2=<<225*2=450>>450 kg in his hands How much weight was the weight vest? ** The weight vest weighed 150*.5=<<150*.5=75>>75 kg How much total weight was Tom moving? ** So he had a total of 450+75=<<450+75=525>>525 kg he was moving #### 525 Jenny signs up for dinner theater with 5 of her friends. Each person pays $50 for the ticket and $10 for their entrée, and half the people also buy unlimited drink tickets for $30/person. Then the dinner theater is canceled due to COVID, and each person gets a 90% refund. How much money did the group of six friends lose? How much did each person pay? ** First find the cost of the ticket and the entrée for each person: $50/person + $10/person = $<<50+10=60>>60/person How much did the group of six friends pay? ** Then multiply that cost by the number of people to find the total cost of entrees and tickets: $60/person * 6 people = $<<60*6=360>>360 How many people ordered drink tickets? ** Now find how many people ordered drink tickets: 6 people / 2 = <<6/2=3>>3 people How much did the group of three friends pay for drink tickets? ** Now find the total cost of the drink tickets: 3 people * $30/person = $<<3*30=90>>90 How much did the group of six friends lose? ** Now find the total cost of the evening: $90 + $360 = $<<90+360=450>>450 How much did the group of six friends get refunded? ** Now multiply this quantity by 90% to find the amount of the refund: $450 * .9 = $<<450*.9=405>>405 How much money did the group of six friends lose? ** Now subtract the refund amount from the total cost to find how much money the friends lost: $450 - $405 = $<<450-405=45>>45 #### 45 There were 15 males and 10 more girls at the party. Each attendee received 2 cans of soft drinks. If Mary bought several boxes of soft drinks where a box contains 8 cans and is priced at $5 for each box, how much did Mary spend on soft drinks? How many girls were there? ** There were 10 + 15 = <<10+15=25>>25 girls in the party. How many people were there? ** So, there were a total of 15 + 25 = <<15+25=40>>40 attendees. How many cans of soft drinks are needed? ** 40 x 2 = <<40*2=80>>80 cans of soft drinks are needed. How many boxes of soft drinks did Mary buy? ** So, Mary bought 80/8 = <<80/8=10>>10 boxes of soft drinks. How much did Mary spend on soft drinks? ** Therefore, Mary spent 10 x $5 = $<<10*5=50>>50 on soft drinks. #### 50 Suzanne wants to raise money for charity by running a 5-kilometer race. Her parents have pledged to donate $10 for her first kilometer and double the donation for every successive kilometer. If Suzanne finishes the race, how much money will her parents donate? How much money will her parents donate for the 2nd kilometer? ** For the 2nd kilometer, the donation will be $10 * 2 = $<<10*2=20>>20. How much money will her parents donate for the 3rd kilometer? ** For the 3rd kilometer, the donation will be $20 * 2 = $<<20*2=40>>40. How much money will her parents donate for the 4th kilometer? ** For the 4th kilometer, the donation will be $40 * 2 = $<<40*2=80>>80. How much money will her parents donate for the final kilometer? ** For the final kilometer, the donation will be $80 * 2 = $<<80*2=160>>160. How much money will her parents donate for the entire race? ** For the entire race the donation will be $10 + $20 + $40 + $80 + $160 = $<<10+20+40+80+160=310>>310. #### 310 Niles is collecting his book club's annual fees. Each of the six members pays $150/year towards snacks, plus $30 each for six hardcover books and $12 each for six paperback books. How much money does Niles collect in total? How much does each hardcover book cost? ** First find the cost per member of the hardcover books: $30/book * 6 books = $<<30*6=180>>180. How much does each paperback book cost? ** Then find the cost per member of the paperback books: $12/book * 6 books = $<<12*6=72>>72. How much does each member pay? ** Then find the total cost per member: $180 + $72 + $150 = $<<180+72+150=402>>402/member. How much money does Niles collect in total? ** Now find the total amount of money by multiplying the cost per member by the number of members: $402/member * 6 members = $<<402*6=2412>>2412. #### 2412 The sky currently has 4 times as many cirrus clouds as cumulus clouds, and 12 times as many cumulus clouds as cumulonimbus clouds. If the sky currently has 3 cumulonimbus clouds, how many cirrus clouds are in the sky at this moment? How many cumulus clouds are in the sky at this moment? ** The sky has 3*12=<<3*12=36>>36 cumulus clouds. How many cirrus clouds are in the sky at this moment? ** The sky has 4*36=<<4*36=144>>144 cirrus clouds. #### 144 Every day, while going to school, Shane drives a total of 10 miles. Calculate the total distance he drives in an 80 day semester from home to school and back. How many miles does Shane drive each day? ** To go to school and back, Shane drives 2*10 = <<2*10=20>>20 miles per day. How many miles does Shane drive in an 80 day semester? ** In 80 days of a semester, he drives for 80*20 = <<80*20=1600>>1600 miles #### 1600 John buys a pair of earbuds that cost $200. If tax was 15%, how much did he pay after tax? How much was the tax? ** The tax was 200*.15=$<<200*.15=30>>30 How much did John pay after tax? ** So he paid 200+30=$<<200+30=230>>230 #### 230