McGraw Hill Glencoe Algebra 2, 2012
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McGraw Hill Glencoe Algebra 2, 2012 View details
1. Expressions and Formulas
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Exercise 38 Page 8

Evaluate different parts of the expression separately.

95.0

Practice makes perfect

The formula that calculates the efficiency rating of a quarterback has several parts and involves several variables. Let's first summarize the information given on Peyton Manning's card.

Variable Description Value
C Passes Completed 371
A Passes Attempted 555
Y Passing Yardage 4002
T Touchdown Passes 27
I Interceptions 12

The efficiency rating formula involves a sum of four terms multiplied by 1006. ( C/A-0.3/0.2+ Y/A-3/4+ T/A/0.05+ 0.095-I/A/0.04 ) * 100/6Let's use the order of operations. We will calculate the four terms separately inside the parentheses, add them up, and then finish with the multiplication outside of the parentheses. Let's start with the first term.

C/A-0.3/0.2
371/555-0.3/0.2
â–¼
Simplify
371/555-3/10/0.2
742/1110-3/10/0.2
742/1110-333/1110/0.2
4091110/0.2
409/222

We can find the other terms in a similar way. The table below contains the results.

Term Expression Value
C/A-0.3/0.2 371/555-0.3/0.2 409/222
Y/A-3/4 4002/555-3/4 779/740
T/A/0.05 27/555/0.05 36/37
0.095-I/A/0.04 0.095-12/555/0.04 543/296

The next step is to add these numbers. Remember to find their common denominator before adding them. 409/222+779/740+36/37+543/296=25 319/4440 As a final step, the formula calls for multiplying the result by 1006. 25 319/4440* 100/6=12 6595/1332 This is the exact value of Peyton Manning's efficiency rating for the 2008 season. The question asks for this rating as a decimal rounded to the nearest tenth, so we need to find the quotient and round the decimal number. Efficiency Rating:12 6595/1332≈ 95.0