Solving Age and Rate Problems with Equations
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This practice session focuses on solving various algebraic equations related to age differences and rates. Students will determine the birth year of a sibling based on age differences, calculate time needed to bake multiple cakes, and solve straightforward equations (e.g., x - 3 = -7). Additionally, algebraic expressions involving variables will be formed to solve real-world problems, including estimating the capacity of an elevator and understanding how long natural processes, like tree carbon absorption, take over time. Ideal for reinforcing algebraic concepts.
Solving Age and Rate Problems with Equations
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Presentation Transcript
Do Now • Mrs. Tilli was born in 1984. She is 14 years older than her little brother Chase. Write and solve an equation to find the year that Chase was born. • Mrs. Cieri can make 2 cakes in an hour. How long will it take her to make 24 cakes? • Solve: x−3= -7 • B+3=10 • -3h=27 • g/5=4
Practice 4-1 • 29 • 30 • 4 • 14 • 24 • 56 • 11 • 28 • 112 • 2n+3 • 16 more than n • 3.2 times n • 25.6 n less than • N divided by 24 • 45 divided by n • 15.4 n less than • M+12 • 6f • A-25 • s/10 • 21a. 5m • 21b. $26.25
Guided Problem Solving 4-1 • Write an algebraic expression for the approximate number of names in p pages of the directory. • A mathematical phrase with at least one variable • The number of pages in the directory • 11 names • 110 names • 440 names • 440 names • 440p names • 440p names • 440; 880; 1,320; yes • 48p
Practice 4-2 • 30 • 99 • 29.6 • 57 • T=5 • W=8 • P=7 • A=13 • H=24 • G=128 • Y=39 • D=16 • W=25 • T=4 • Y=10.64 • X=104.97 • 210+x=520; about 300 cans • $25.30x=$227.70; about 10 bolts of fabric • $.79x=$11.85; 15 balloons
Guided Problem Solving 4-2 • 2,000 lb; 55-lb boxes • Write an equation to estimate the number of boxes you can safely place on the elevator at one time. • The number of boxes • 2,000 lbs • 55 lb • 55x=2,000 • 36 boxes • Yes; 36 boxes × 55 lb/box=1,980 lb • 65x=5,000; x is about 77 minutes or 1 hour 17 minutes
Practice 4-4 • 14 • -243 • -28 • -18 • 36 • 48 • -7 • -7 • 16 • -52 • -7 • -126 • -96 • -5 • 4 • 288 • -399 • 1,386 • -4 • -8,918 • -113 • -50 • 15n=240, n=16; 16 flowers • 10,500/n=1,500, n=7; 7 gal
Guided Problem Solving 4-4 • 26 lb; 390 lb • Find the number of years it will take for a tree to absorb 390 lb of carbon dioxide • Multiplication; the number of years times the amount of carbon dioxide a tree absorbs each year equals the total amount of carbon dioxide absorbed. • 26 lb • 26y lb • 26y=390 • Y=15 • 15 years • 26y=390; 26 ×15=390; 390=390 • 8x=1000; x=125 days