Quiz & test questions Grade 7 Math

Selwyn Household Water Use: A Grade 7 Rates and Percent Quiz

A grade 7 quiz on the fictional Selwyn household, mixing multiple-choice, computation, and a probability item across percent and unit-rate reasoning on daily water use.

Grade: Grade 7
Subject: Math
Material: Quiz & test questions
Time: 30 min
Prep: No prep
Materials: Calculator (optional)

Standards

7.RP.A.3 Common Core Math

Use proportional relationships to solve multistep ratio and percent problems. Examples: simple interest, tax, markups and markdowns, gratuities and commissions, fees, percent increase and decrease, percent error.

How this material aligns: Items 2, 3, 4, and 5 use proportional reasoning to find a percent of a total and a part's share of daily use, the multistep percent work at the center of this standard.

All materials for 7.RP.A.3 →

7.SP.C.5 Common Core Math

Understand that the probability of a chance event is a number between 0 and 1 that expresses the likelihood of the event occurring, with larger numbers indicating greater likelihood.

How this material aligns: Item 7 asks students to express the chance of a dripping-faucet day as a fraction and a decimal between 0 and 1 from past frequency, exactly the probability idea this standard defines.

All materials for 7.SP.C.5 →

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This material is in the public domain (CC0) and may be copied, edited, and shared freely, without attribution. Updated 2026-07-23.

Objectives

Students will calculate percents and shares of a household's daily water use.
Students will express a chance event as a probability between 0 and 1.

Vocabulary

Key words: percent, unit rate, probability

Teacher overview

This 30-minute quiz is worth 25 points and checks whether grade 7 students can apply percent and unit-rate reasoning, plus a first idea of probability, to household water use. It mixes one multiple-choice item, five computation items, one short-answer item, and one probability item, all built around a fictional family, the Selwyns. The national figures it uses come from public water-use data; the family's specific choices are invented for the quiz. Teachers can use it as an end-of-unit check or split the probability item off as a separate exit ticket.

Selwyn Household Water Use: A Grade 7 Rates and Percent Quiz — Grade 7 Math

Name: ____________________________ Date: ______________

Assessment

The Selwyn family is fictional. The average US household uses about 300 gallons of water a day. Use this figure where a question calls for it.

(2 points) About what percent of an average household's water is used indoors?
- A) 24%
- B) 50%
- C) 70%
- D) 97%
(3 points) The Selwyns use the average 300 gallons a day. How many of those gallons are used indoors, at 70%?
(3 points) A 2016 Water Research Foundation study of single-family homes found that toilets were about 24% of indoor use. Using your indoor total from item 2, how many gallons go to toilets? Round to the nearest tenth.
(3 points) A standard showerhead flows at 2.5 gallons per minute. How many gallons does an 8-minute shower use?
(3 points) What percent of the family's 300-gallon daily total is that one 20-gallon shower? Round to the nearest whole percent.
(3 points) A water-saving showerhead flows at 2.0 gallons per minute instead of 2.5. Explain in a sentence why switching would lower the shower's share of daily use.
(4 points) Over 50 days, the Selwyns found a dripping faucet on 6 of those days. Based on that, what is the probability that a random day has a dripping faucet? Give a fraction and a decimal between 0 and 1.
(4 points) EPA WaterSense says a faucet dripping once per second can waste more than 3,000 gallons a year. Using 3,000 gallons a year, if the family fixes it after one-third of a year, about how many gallons did it waste in that time?

From Water for Schools (waterforschools.org). This material is in the public domain (CC0) and may be copied, edited, and shared freely.

Answer Key

Answer: C) 70%.
Public water-use data puts about 70% of average household use indoors, so C is correct.
Answer: 210 gallons.
300 × 0.70 = 210 gallons used indoors.
Answer: 50.4 gallons.
0.24 × 210 = 50.4 gallons go to toilets.
Answer: 20 gallons.
2.5 gallons per minute × 8 minutes = 20 gallons.
Answer: 7%.
20 ÷ 300 = 0.0667, which rounds to about 7%.
Answer: It uses less water each minute.
A 2.0-gallon-per-minute head uses fewer gallons over the same shower time than a 2.5-gallon-per-minute head, so the shower is a smaller share of the daily total.
Answer: 0.12.
6 out of 50 days is the fraction 6/50, which equals 0.12, a number between 0 and 1.
Answer: 1,000 gallons.
One-third of 3,000 gallons is 3,000 ÷ 3 = 1,000 gallons wasted before the fix.

Differentiation

Support

Provide a formula reminder card showing "part = percent × whole" with item 2 set up as 300 × 0.70, and allow a calculator on every computation item. Let students answer item 6 with a sentence frame rather than open-ended writing.

Extension

Ask students to find how many gallons a week the family would save by switching every 8-minute shower to the water-saving head, assuming one shower per person per day for a four-person household. Have them state the weekly savings and the percent reduction per shower.

ELL supports

Pre-teach "indoors," "share," and "probability" with a simple pie picture of daily use and a 0-to-1 number line. Provide the frame "the chance is ___ out of ___, which is ___" for item 7 so students can state the probability in words before writing the decimal.

Extensions

Have students track their own household's showers or faucet minutes for two days using a simple tally, then estimate their daily shower gallons with the 2.5-gallons-per-minute rate. Comparing their estimate with the Selwyn quiz figures turns the percent work into a look at their own water use.