Answer
Total number of 7's needed = 20
Work Step by Step
Number of 7's in each group of 10 from 1 to 99 = 10
Other than this, there will be 10 additional 7's from 70 to 79 .
10 + 10 = 20
therefore, total no of 7's required = 20
Thinking Mathematically (6th Edition)
by Blitzer, Robert F.
Published by
Pearson
ISBN 10:
0321867327
ISBN 13:
978-0-32186-732-2
Chapter 1 - Problem Solving and Critical Thinking - 1.3 Problem Solving - Exercise Set 1.3 - Page 41: 60
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