# Commercial Algebra Volume 1

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## Description

This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1917 edition. Excerpt: ...number. 115. Two Unknowns, One Letter. A problem may involve the finding of the values of two unknown quantities and still require the use of only a single letter if there are two statements either expressed or implied. As will be seen, one statement will give a relation which makes it possible to represent the two unknowns by the aid of only a single letter, but with different coefficients; the other statement will be one which can be translated into an equation. 1. On June 21 daylight in a certain place lasts 8 hr. longer than darkness. How many hours are daylight? Statement I. Daylight = darkness + 8 hr.. Statement II (implied). Daylight + darkness = 24 hr. Let x = the number of hours of darkness. Then, from I, x + 8 = the number of hours of daylight. But because, from Statement II, 2. A clerk counting change consisting of dimes and quarters remembers that there were 45 coins and that their total value was \$8.40. How many were there of each? Statement I. Number of quarters + number of dimes = 45. Statement II. Value of quarters + value of dimes = \$8.40. Let x = the number of quarters. Then, from Statement I, 45--x--the number of dimes. Multiplying 25 by the number of quarters and 10 by the number of dimes, to find the values in cents, we have 25 x + 10 (45-x) = 840. Solving, x = 26, the number of quarters. Hence 45--x = 19, the number of dimes. Exercise 92. Problems Examples 1 to 9, oral 1. Five more than three times a certain number is 20. What is the number? 2. The sum of two numbers is 34 and one of the numbers is 19. What is the other number? 3. The difference between two numbers is 17 and the larger number is 32. What is the smaller number? 4. The difference between two numbers is 41 and the smaller number is 19. What is the...show more

## Product details

• Paperback | 54 pages
• 189 x 246 x 3mm | 113g
• United States
• English
• black & white illustrations
• 1236806808
• 9781236806802