There are 25 different layers of rock in a canyon’s strata. Five of the layers are limestone. Half of the rest are sandstone. Four of the remaining are quartz. Half of the rest are shale. The rest are all different kinds of rock. How many kinds of rock make up only one layer in the canyon’s strata?

There are 25 - 5 =

<<25-5=20>>20 layers of rock that are not limestone. Half of those 20 are sandstone, so there are 20 / 2 = <<20/2=10>>10 that are not limestone or sandstone. Four of those are quartz, so 10 - 4 = <<10-4=6>>6 layers are not limestone, sandstone, or quartz. Half of the rest are shale, so 6 / 2 = <<6/2=3>>3 kinds of rock remain that make up only one layer in the strata. #### 3 Micah picks 2 dozen strawberries from the field. He eats 6 and saves the rest for his mom. How many strawberries are there for his mom? Micah picks 2 x 12 = <<2*12=24>>24 strawberries. After he eats 6, there are this many strawberries left for his mom: 24 - 6 = <<24-6=18>>18. #### 18 One barnyard owl makes 5 hoot sounds per minute. If 5 less than 20 hoots per minute are heard coming out of the barn, how many Barnyard owls would this noise be coming from? 5 less than 20 hoots per minute is 20-5=<<20-5=15>>15 hoots per minute. If one barnyard owl makes 5 hoot sounds per minute, then 15 hoots per minute are coming from 15/5=<<15/5=3>>3 barnyard owls. #### 3 Hayes does 3 loads of laundry a week using a detergent pod for each load. His detergent pods come 39 to a pack. How many packs of detergent pods will he need to do a full year of laundry? He uses 3 detergent pods a week and there are 52 weeks in a year, so he uses 3*52 = <<3*52=156>>156 His detergent has 39 pods per pack and he needs 156 pods, so he will need 156/39 = <<156/39=4>>4 packs of detergent pods #### 4 There are 336 books in a library. On Monday, 124 books are taken out. On Tuesday, 22 books are brought back. How many books are there now? At the end of Monday, there are 336 - 124 = <<336-124=212>>212 books left. At the end of Tuesday, there are 212 + 22 = <<212+22=234>>234 books. #### 234 Carla needs to drive her car to do a bunch of errands. She needs to drive 8 miles to the grocery store, 6 miles to pick up her kids from school, 12 miles to drop her kids off at soccer practice, and twice the distance from the school to soccer practice to get everyone home again. If Carla's car gets 25 miles per gallon, and gas costs $2.50, how much will Carla have to spend on gas for her trip? First find the distance between soccer practice and home by multiplying the distance between soccer practice and school by 2: 12 miles * 2 = <<12*2=24>>24 miles Then find the total distance Carla drives by adding the length of each trip: 24 miles + 12 miles + 6 miles + 8 miles = <<24+12+6+8=50>>50 miles Then find how many gallons of gas she needs by dividing the distance of the trip by her car's gas mileage: 50 miles / 25 mpg = <<50/25=2>>2 gallons Then multiple the gallons of gas by the price per gallon to find the total cost: 2 gallons * $2.50 = $<<2*2.5=5>>5 #### 5 On Monday, Mack writes in his journal for 60 minutes at a rate of 1 page every 30 minutes. On Tuesday, Mack writes in his journal for 45 minutes at a rate of 1 page every 15 minutes. On Wednesday, Mack writes 5 pages in his journal. How many pages total does Mack write in his journal from Monday to Wednesday? On Monday, Mack writes 60 / 30 = <<60/30=2>>2 pages On Tuesday, Mack writes 45 / 15 = <<45/15=3>>3 pages In total, from Monday to Wednesday, Mack writes 2 + 3 + 5 = <<2+3+5=10>>10 pages #### 10 Jason is making a salad. The lettuce has 30 calories, the cucumber has 80 calories, and the 12 croutons have 20 calories each. How many calories are in the salad? In total, the 12 croutons have 20 calories/crouton * 12 croutons = <<20*12=240>>240 calories. Together, the croutons, lettuce and cucumber have 240 + 30 + 80 = <<240+30+80=350>>350 calories #### 350 James buys 3 dirt bikes for $150 each and 4 off-road vehicles for $300 each. It also cost him $25 to register each of these. How much did he pay for everything? The dirtbikes cost 3*150=$<<3*150=450>>450 The off-road vehicles cost 300*4=$<<300*4=1200>>1200 He had to register 3+4=<<3+4=7>>7 vehicles That means registration cost 25*7=$<<25*7=175>>175 So the total cost of everything was 450+1200+175=$<<450+1200+175=1825>>1825 #### 1825 A one-way ticket costs $2. A 30-day pass costs $50. What's the minimum number of rides you will need to take every month so that the 30-day pass is strictly cheaper per ride? For the 30-day pass to be cheaper, then the average fare should be cheaper than the $2 one-way ticket. If the 30-day pass costs $50, then I should take at least $50/$2=<<50/2=25>>25 rides to pay the same as a one-way ticket However, given that we want the 30-day pass per ride to be strictly cheaper we should ride at least 25+1=26 times #### 26