Copyright © The McGraw-Hill Companies, Inc. Permission is granted to reproduce for classroom use. NAME ___________________________________________________ DATE _____________________ PERIOD __________ Lesson 3 Problem-Solving Practice Multiplying and Dividing Monomials 1. Ms. Masse’s biology class is conducting an experiment to record the growth of a certain kind of bacteria. Each student has a lab dish containing 2 bacteria which are able to double every day. How many bacteria will be present in a student’s lab dish after two weeks? 2. In 1995, the average home computer had a speed of about 10 6 cycles per second. In 2004, the average home computer had a speed of about 10 9 cycles per second. How many times faster were the computers in 2004 as compared to those in 1995? 3. A catering company is planning an event for 2 7 people. One week before the event, they find out that the number of people has doubled. Will there be 2 8 or 2 14 people at the event? Explain. 4. Vance and Ko are trying to simplify the expression 3 8 × 3 7 . Their answers are different: Ko’s work: 3 8 × 3 7 = (3 × 3) (8 + 7) = 9 15 Vance’s work: 3 8 × 3 7 = 3 (8 + 7) = 3 15 Which student is correct? Identify the mistake made by the other student. 5. Levels of audible sound are measured in decibels (dB). An increase in 10 dB is considered a doubling (2 1 ) of perceivable sound to the human ear. The table below lists the decibel level of some common sounds. Sound Level (dB) Source 30 Library, no talking 70 Busy traffic 80 Hair dryer 100 Garbage truck 110 Rock concert 120 Jet engine 180 Rocket launching pad How many times louder is a jet engine than a hair dryer? 6. Refer to the table in Exercise 5. How many times louder is it at a rocket launching pad than in a library? Math Accelerated • Chapter 4 Powers and Roots