Mary is counting the number of minnows in the pond. 40% of the minnows have red bellies, 30% have green bellies and the rest have white bellies. If 20 minnows have red bellies, how many minnows have white bellies?

First find the total number of minnows by dividing the number of red minnows by the percentage of minnows that are red: 20 minnows / 40% = 50 minnows

Then subtract the percentages of red- and green-bellied minnows to find the percentage of white-bellied minnows: 100% - 40% - 30% = 30%

Then multiply the total number of minnows by the percentage that have white bellies: 30% * 50 minnows =

<<30*.01*50=15>>15 minnows #### 15 The number of short students in a class is 2/5 of the total number of students. If there are 90 tall students, and the class has 400 students, calculate the total number of students with average height. The number of short students in the class is 2/5*400 = <<2/5*400=160>>160 The total number of short and tall students is 160+90 = <<160+90=250>>250 Since there are 400 students in the class, the number of students with average height is 400-250 = <<400-250=150>>150 #### 150 The distance across a country is 8205 kilometers. Amelia started at one end and drove 907 kilometers on Monday and 582 kilometers on Tuesday. How many kilometers does Amelia still have to drive to make it across the country? Distance driven = 907 + 582 = <<907+582=1489>>1489 km Distance remaining = 8205 - 1489 = <<8205-1489=6716>>6716 km Amelia still has 6716 kilometers to drive. #### 6716 Theo can eat 13 cookies, 3 times a day, 20 days each month. How many cookies can he eat in 3 months? The total amount of cookies he can eat in a day is 13 x 3 = <<13*3=39>>39. The total amount of cookies he can eat in a month is 39 x 20 = <<39*20=780>>780. Therefore, the total amount of cookies he can eat in 3 months is 780 x 3 = <<780*3=2340>>2340. #### 2340 Mary and Mike are sharing a jar of paint. Mary paints a dragon using 3 square feet worth of paint. Mike paints a castle using 2 square feet more paint than Mary used on her dragon. They both then work together to paint the biggest sun possible. If there was originally enough paint in the jar to cover 13 square feet, how many square feet of paint can be used to paint the sun? The castle uses 3 + 2 = <<3+2=5>>5 square feet of paint. The sun uses 13 - 3 - 5 = <<13-3-5=5>>5 square feet of paint. #### 5 There are 92 students altogether. Twenty of them ride the school bus home together, 5/8 of the remaining ride their own bike home, and the rest whose houses are near the school walk home. How many students are walking home? If there are 92 students and 20 students take the bus home, the number of students who haven't taken the bus is 92-20 = <<92-20=72>>72 students. 5/8 of the students who didn't take the bus home ride bikes home, a total of 5/8* 72 = <<5/8*72=45>>45 students. The number of students who neither took the bus nor biked home but walked home is 72-45 = <<72-45=27>>27 #### 27 Maya wants to learn how to lift and right now she can only lift a fourth of what America can. America can lift 240 pounds. As Maya grows stronger, she can add 10 more pounds to what she previously could lift. America follows this and now she has hit her peak lift at 300 pounds. If Maya reaches her absolute peak and can lift half of what America can lift, how many more pounds can Maya lift now than when she started? Maya can lift 240*0.25=<<240*0.25=60>>60 pounds. Gaining progress, she can lift up to 60+10=<<60+10=70>>70 pounds. At her peak, she can lift 300*0.5=<<300*0.5=150>>150 pounds. Maya's peak is 150 pounds - 60 pounds when she started = <<150-60=90>>90 more pounds than when she started. #### 90 Jean has three times as much money as Jane. They have a combined total of $76. How much money does Jean have? Let's assume the total amount of money that Jane has is m. Since Jean has 3 times as much money as Jane, he has 3*m=3m Combined, Jean and Jane have a total of m+3m = $76 This evaluates to 4m=$76 The total amount of money that Jane has, represented by m, is m=$76/4 Jane has m=$<<19=19>>19 Since Jean has three times as much money as Jane, Jean has 3*$19=$57 #### 57 Carter grew 9 plants with 3 seed packets. How many more seed packets does Carter need to have a total of 12 plants in his backyard? If he grows 9 plants with 3 seed packets, he grows 9/3=<<9/3=3>>3 plants with 1 seed packet. Since 1 seed packet grows 3 plants, he'll need 1 more to make the plants 12. #### 1 Kimberly went hiking and took a 4-liter bottle full of water with her. The first time she drank from it, she consumed a quarter of the water in the bottle. Later on, she drank 2/3rd of the remaining water. How much water is left in the bottle (in liters)? Her first drink consumed 1/4 * 4 = <<1/4*4=1>>1 liter of water. Thus there were 4 - 1 = <<4-1=3>>3 liters of water left in the bottle. Next, she drank 2/3 * 3 = <<2/3*3=2>>2 liters. Thus, there were 3 - 2 = <<3-2=1>>1 liters remaining. #### 1