كتاب الطالب الرياضيات Reveal الصف الثامن منهج انجليزي الفصل الأول
. OPERA Aran's drama class is planning a field trip to see Mozart's famous opera Don Giovanni. Tickets cost $39 each, and there are 23 students and 2 teachers going on the field trip
a. Write an expression to find the group's total ticket cost
b. What is the group's total ticket cost
. SALARY In a recent year, the median salary for an engineer in the United States was $55,000 and the median salary for a computer programmer was $52,000
a. Write an expression to estimate the total cost for a business to employ an engineer and a programmer for 5 years
b. Estimate the total cost for a business to employ an engineer and a programmer for 5 years
. COSTUMES Isabella's ballet class is performing a spring recital for which they
need butterfly costumes. Each butterfly costume is made from 3 d yards of fabric
a. Write an expression to find the number of yards of fabric needed for 10 costumes
b. Use the Distributive Properw to find the number of yards of fabric needed for 10 costumes. Show your work. (Hint: A mixed number can be written as the sum of an integer and a fraction
. REASONING Letisha and Noelle each opened a. checking account, a savings account, and a college fund. The chart shows the amounts that they deposit
into each account every month
a. Write an expression to find the amount in Letisha's checking. savings, and college accounts after 12 months
b. How much is in Letishs checking, savings, and college accounts after 12 months
Practice
Example 1
I. POOLS The accuracy of a pool thermometer is the positive difference between the temperature reading on the thermometer t and the actual temperature of the pool
p. Write two absolute value expressions equivalent to the accuracy of a pool
thermometer
. ROLLERCOASTER At a theme park. a must be a certain height to ride a rollercoaster. A person must be h inches tall. plus or minus 1.5 inches. Anoki says the absolute value expression 11.5 — hl represents an acceptable height. David says the absolute value expression lh — 1.51 represents an acceptable height. Who is correct ? Explain
. WATER DEPTH An echo sounder is a device used to determine the depth of water by measuring the time it takes a sound produced just below the water surface to return, or echo. from the of the body of water. The accuracy of an echo sounder is the positive difference between the depth of water reading on the echo sounder r and the actual depth of water w. Write two absolute value expressions equivalent to the accuracy of an echo sounder
. GOLF A certain company designs and ships boxes of golf balls. Each box must weigh 540 grams. Write two absolute value expressions that represent the number of grams a box weighing g grams is away from the desired weight
Practice
Example 1
. TEST SCORES A teacher compares the ratio of the number of questions answered correctly to the total of questions on a test as a metric. For a student to earn an A or B on a test, the ratio must greater than or equal to 0.8. The last test given by the teacher had a total of 40 questions. using this metric. what is the least number of questions a student can answer correctly to earn an A or B on the test
. DRIVERS TEST The Department of Motor Vehicles, DMV, uses a metric to determine whether a earns a driver's license. In one state, the total number of IX)ssible points on the written portion of the driver's exam is 46. A will pass the written portion of the driver's exam by scoring 84% or greater. The table shows the number of points different people earned on the written portion of the driver's exam. How many people passed the written portion of the driver's exam
. TRACK A college track coach compares the ratio of time it takes a runner to run 100 meters to 12 seconds. For a runner to be on the team, the ratio must less than or equal to 0.95. What is the slowest time 100 meters can be run to make the team
Example 2
. DEBT-TO-INCOME RATIO Find Jada's debt-to-income ratio if her monthly are $1850 and her monthly salary is $2500
. DEBT-TO-INCOME RATIO Find Victoria' debt-to-income ratio if her monthly expenses are $1280 and her monthly salary is $2500
. PLUMBING Raven is deciding between two plumbing services. Service Provider A multiplies the average number of hours spent at a residence by $50. where the average number of hours spent at a residence is 1.5 hours for a new house and 3.75 hours for an old house. Service Provider B multiplies the exact number of hours spent at a residence by $60. Suppose Raven has a new house and needs a plumber for 1.75 hours. Find the cost of service charge using both methods
. INVESTING Hector is deciding how much he should invest each year. The Automatic Method multiplies the average income by 10%. where the average income is $50,000 for an employee that has been at the same company for 10 years or less and for an employee that has been at the same company for more than 10 years. The Exact Method multiplies the exact income by 7.5%. Suppose Hector has been at the same company for 12 years and his income last year was $75,000. Find the amount Hector should invest using both methods
Mixed Exercises
. PRECISION A GPS is a device that can be used to determine the distance a ball is from a pin. The accuracy of a golf GPS is the difference the distance a golf ball is from a pin on the golf GPS g and the actual distance a golf ball is from a pin
a. Write two absolute value expressions equivalent to the of a golf GPS
b. Evaluate the expression if the actual distance from the golf ball to the pin is 70 meters and the distance the ball is from the pin on the golf GPS is 75 meters
STRUCTURE The students in Mrs. Mangiones class attempt to guess the number Of marbles in a jar to earn 2 extra credit on their next exam. Suppose there are 1206 marbles in a jar and a student makes a guess of m marbles
a. Write two absolute value expressions that represent the difference between the guess and the actual number of marbles in the jar
b. Evaluate the expression if a student guesses there are 1100 marbles in the jar
. CREATE Describe a real-world situation that could be represented by the absolute value expression lx — 891
FIND THE ERROR The accuracy of a rain is the positive difference the amount of rain in the rain gauge g and the actual amount of rain r. Sam says the absolute value expression Igl — Irl is equivalent to the accuracy of a rain gauge. Is Sam correct? Explain your reasoning
. ANALYZE Diaz claims that if a and b are real numbers. then la + bl is always equal to Determine whether his claim is true or false. Justify your argument