Human beings are made up of about 70% water. José weighs 80 pounds. How much of his body weight is water?

A. 10 pounds
B. 56 pounds
C. 70 pounds
D. 79.3 pounds

(80 lbs. X 0.70)

Dogs are made up of about 63% water. One gallon of water weighs about 8.3 pounds. Kinetta’s dog weighs 50 pounds. How many gallons of water does Kinetta’s dog contain? Use the space below to show your work and write your answer on the line.

Human beings are made up of about 70% water. On the outline of a human body below, shade in the portion that represents about how much is made up of water.

Graphic of an outline of a human being such as the one on page 64 of the Project WET Guide.

Benchmarks: Grades 3-5 — MA.A.3.2.2, MA.A.3.2.3, MA.B.1.2.2; Grades 6-8 — MA.3.3.2, MA.A.3.3.3

Difficulty Level: Grades 3-5 — Medium; Grades 6-8 — Easy

63% water = 63 / 100 = 0.63 water
50 pounds X 0.63 = 31.5 pounds of water
31.5 pounds of water / 8.3 pounds/gallon = 3.8 gallons
3.8 gallons

4-Point Response

1. Student correctly converts percent of water weight to a decimal.
2. Student correctly multiplies the dog’s weight by the converted percent.
3. Student correctly divides the dog’s water weight in pounds by the number of pounds per gallon.
4. Student correctly labels answer.

OR

1. Student correctly uses ratio to calculate the dog’s water weight:
    a. 63 / 100 = 0.63
    b. 0.63 X 50 = 31.5
    c. 31.5 X 100 = 3,150
    d. X = 3,150 / 100 = 31.5 pounds of water
2. Student correctly divides the dog’s water weight in pounds by the number of pounds per gallon.
3. Student correctly labels answer.

3-Point Response

1. Student correctly converts percent of water weight to a decimal.
2. Student correctly multiplies the dog’s weight by the converted percent, but makes a mathematical error.
3. Student correctly divides the dog’s water weight in pounds by the number of pounds per gallon, and continues the mathematical error.
4. Student correctly labels answer.

OR

1. Student correctly uses ratio to calculate the dog’s water weight:
    a. 63 / 100 = 0.63
    b. 0.63 X 50 = 31.5
    c. 31.5 X 100 = 3,150
    d. X = 3,150 / 100 = 31.5 pounds of water but makes a mathematical error.
2. Student correctly divides the dog’s water weight in pounds by the number of pounds per gallon, and continues the mathematical error.
3. Student correctly labels answer.

OR

1. Student correctly converts percent of water weight to a decimal.
2. Student correctly multiplies the dog’s weight by the converted percent.
3. Student correctly divides the dog’s water weight in pounds by the number of pounds per gallon, but makes a mathematical error.
4. Student correctly labels answer.

OR

1. Student correctly converts percent of water weight to a decimal.
2. Student correctly multiplies the dog’s weight by the converted percent.
3. Student correctly divides the dog’s water weight in pounds by the number of pounds per gallon.
4. Student does not label answer or does not write answer on line.

2-Point Response

1. Student correctly converts percent of water weight to a decimal.
2. Student correctly multiplies the dog’s weight by the converted percent, the dog’s water weight in pounds by the number of pounds per gallon.

OR

1. Student correctly uses ratio to calculate the dog’s water weight:
    a. 63 / 100 = 0.63
    b. 0.63 X 50 = 31.5
    c. 31.5 X 100 = 3,150
    d. X = 3,150 / 100 = 31.5 pounds of water.
2. Student does not divide the dog’s water weight in pounds by the number of pounds per gallon.

OR

Student correctly answers and labels questions, but does not show work.

1-Point Response

1. Student does not convert percent of water weight to a decimal, but multiplies the dog’s weight by 63.
2. Student correctly divides the dog’s water weight in pounds by the number of pounds per gallon, but continues the error.

OR

1. Student incorrectly uses ratio to calculate the dog’s water weight:
    a. 63 / 100
    b. 50 / X
    c. 63 X = 5000
    d. X = 5,000 / 63 = 79 pounds of water
2. Student correctly divides the dog’s water weight in pounds by the number of pounds per gallon, but continues the mathematical error.

Benchmarks: Grades 3-5 — MA.A.3.2.2, MA.A.3.2.3, MA.B.1.2.2; Grades 6-8 — MA.3.3.2, MA.A.3.3.3

Difficulty Level: Grades 3-5 — Hard; Grades 6-8 — Medium

2-Point Response

1-Point Response

Benchmarks: Grades 3-5 — MA.B.1.2.1

Difficulty Level: Grades 3-5 — Easy