Sarah's age is equal to three times Mark's age minus 4. Mark is four years older than Billy. Billy is half Ana's age. If Ana will be 15 in 3 years, how old is Sarah?

How old is Ana right now? ** First figure out how old Ana is right now by subtracting 3 from 15: 15 - 3 =

<<15-3=12>>12 How old is Billy? ** Next, figure out how old Billy is by dividing Ana's age by 2: 12 / 2 = <<6=6>>6 How old is Mark? ** Now figure out how old Mark is by adding 4 to Billy's age: 6 + 4 = <<6+4=10>>10 How old is Mark? ** Now, to figure out Sarah's age, first multiply Mark's age by 3: 10 * 3 = <<10*3=30>>30 How old is Sarah? ** Finally, subtract 4 from triple Mark's age to find Sarah's age: 30 - 4 = <<30-4=26>>26 #### 26 Jake is watching a new show, and is worried about how much time he has spent watching it. He spent half the day on Monday watching his show, 4 hours on Tuesday watching his show, a quarter of the day on Wednesday watching his show, and he spent half as much time watching the show on Thursday as he had done in total throughout the previous few days. On Friday, he finally finished watching it. If the entire show is 52 hours long, how many hours did Jake watch on Friday? How many hours did Jake watch on Monday? ** On Monday, Jake watched 24 hours / 2 = <<24/2=12>>12 hours. How many hours did Jake watch on Wednesday? ** On Wednesday, he watched 24 hours / 4 = <<24/4=6>>6 hours. How many hours did Jake watch from Monday to Wednesday? ** So from Monday to Wednesday, he watched a total of 12 Monday hours + 4 Tuesday hours + 6 Wednesday hours = <<12+4+6=22>>22 hours. How many hours did Jake watch on Thursday? ** He watched half of this on Thursday, which is 22 hours / 2 = <<22/2=11>>11 hours. How many hours did Jake watch from Monday to Thursday? ** So from Monday to Thursday, he watched 22 + 11 = <<22+11=33>>33 hours. How many hours did Jake watch on Friday? ** To finish the show on Friday, he must have therefore watched 52 – 33 = <<52-33=19>>19 hours. #### 19 Martin has 18 goldfish. Each week 5 goldfish die. Martin purchases 3 new goldfish every week. How many goldfish will Martin have in 7 weeks? How many goldfish die in 7 weeks? ** In 7 weeks 5*7 = <<35=35>>35 goldfish die. How many goldfish does Martin purchase 7 weeks? ** In 7 weeks, Martin purchases 3*7 = <<3*7=21>>21 goldfish. How many goldfish will Martin have in 7 weeks? ** In 7 weeks, Martin will have 18-35+21 = <<18-35+21=4>>4 goldfish. #### 4 Stacy is a high school Calculus teacher. She assigns 45 problems for homework. There are twice as many multiple choice problems as free response, and 7 more free response than true/false. How many true/false questions are there? Define a variable ** Let x represent the number of true/false questions How many free response problems are there? ** Free response:x+7 How many multiple choice problems are there? ** Multiple choice: 2(x+7)=2x+14 Write an equation ** Total:x+x+7+2x+14=45 Combine like terms ** 4x+21=45 Subtract 21 from each side ** 4x=24 Divide by 4 ** x=<<6=6>>6 true/false questions #### 6 I bought a TV for $1700 excluding tax. What is the price of the television when calculating 15% of the value-added tax? How much is the value-added tax? ** The value-added tax is 1700*15% = <<1700*15*.01=255>>255. What is the price of the television when calculating 15% of the value-added tax? ** The price of the television including tax 1700+255 = $<<1700+255=1955>>1955. #### 1955 A merchant bought 15 keyboards and 25 printers for a total of $2050. If a keyboard costs $20, how much does a printer cost? How much do the keyboards cost? ** 15 keyboards at $20 per keyboard cost a total of 15*$20=$<<15*20=300>>300 How much do the printers cost? ** The total cost of printers and keyboards is $2050 so 25 printers cost $2050-$300=$<<2050-300=1750>>1750 How much does a printer cost? ** 1 printer cost $1750/25=$<<1750/25=70>>70 #### 70 Frank is walking through a corn maze. He has already spent 45 minutes inside. He has done 4 other corn mazes and finished those in 50 minutes on average. How much longer can he spend inside if he wants to ensure that his average doesn't go above 60 minutes per maze? How many minutes did Frank spend in the other corn mazes? ** He needs to keep his total time at 300 or below because 5 x 60 = <<5*60=300>>300 How many minutes did Frank spend in the other corn mazes? ** His total time spent in the other mazes is 200 because 4 x 50 = <<4*50=200>>200 How many minutes did Frank spend in the other corn mazes? ** His total time spent in the five mazes thus far is 245 because 200 + 45 = <<200+45=245>>245 How many minutes can Frank spend in this corn maze? ** He can spend 55 more minutes on this maze before his average go above 60 because 300 - 245 = <<300-245=55>>55 #### 55 A train travels 270 miles in 3 hours. At the same rate, how many additional hours would it take to travel an additional 180 miles? How fast does the train travel? ** The rate is 270/3=<<270/3=90>>90 mph. How many hours would it take to travel an additional 180 miles? ** Then it takes an additional 180/90=<<180/90=2>>2 hours. #### 2 Marcus can fit 5 pies in his oven at once. He bakes 7 batches of pies, then slips and drops 8 of them. How many pies are left? How many pies does Marcus bake? ** First find the total number of pies Marcus bakes: 5 pies/batch * 7 batches = <<5*7=35>>35 pies How many pies does Marcus bake? ** Then subtract the number of pies Marcus drops: 35 pies - 8 pies = <<35-8=27>>27 pies #### 27 James and Lisa ordered 2 small pizzas. Each pizza has 6 slices. James ate 2/3 of all the slices. How many slices of pizza did James eat? How many slices are there? ** There are a total of 2 * 6 = <<2*6=12>>12 slices of pizza. How many slices did James eat? ** Since James ate 2/3 of all the slices, he ate 2/3 * 12 = <<2/3*12=8>>8 slices of pizza. #### 8