Question

name____ period____ 2.2 calculate the specified value. round to the nearest hundredths place if necessary. 1. what percent of 126 is 22? 2. 25.7 is what percent of 141? 3. 62% of what is 89.3? 4. 120% of 118 is what? 5. what percent of 88.6 is 70? 6. a student earned a grade of 80% on a math test that had 20 problems. how many problems did the student answer correctly? 7. there are 36 carpenters in a crew. on a certain day 29 were present. what percent showed up for work? 8. a metal bar weighs 8.15 ounces. 93% of the bar is silver. how many ounces of silver are in the bar? 9. bob found a wrecked trans - am that he could fix. he bought the car for 65% of the original price of $7200. what did he pay for the car? 10. pamela bought an electric drill at 85% of the regular price. she paid $32.89 for the drill. what was the regular price?

Explanation:

Step1: Recall percentage formula

The formula for finding what percent $a$ is of $b$ is $\frac{a}{b}\times100\%$. For finding $x$ when $p\%$ of $x$ is $y$, we use the formula $x=\frac{y}{p\%}$ (where $p\%$ is written as a decimal), and for finding $y$ when $p\%$ of $a$ is $y$, we use $y = p\%\times a$.

Step2: Solve problem 1

We want to find what percent of 126 is 22. Using the formula $\frac{a}{b}\times100\%$, we have $\frac{22}{126}\times100\%=\frac{2200}{126}\approx 17.46\%$.

Step3: Solve problem 2

We want to find what percent 25.7 is of 141. Using the formula $\frac{a}{b}\times100\%$, we get $\frac{25.7}{141}\times100\%=\frac{2570}{141}\approx 18.23\%$.

Step4: Solve problem 3

We know that 62% (or 0.62 as a decimal) of a number is 89.3. Using the formula $x=\frac{y}{p\%}$, we have $x = \frac{89.3}{0.62}=144.03$.

Step5: Solve problem 4

We want to find 120% (or 1.2 as a decimal) of 118. Using the formula $y=p\%\times a$, we get $y=1.2\times118 = 141.6$.

Step6: Solve problem 5

We want to find what percent of 88.6 is 70. Using the formula $\frac{a}{b}\times100\%$, we have $\frac{70}{88.6}\times100\%=\frac{7000}{88.6}\approx 78.90\%$.

Step7: Solve problem 6

A student got 80% on a 20 - problem test. Using the formula $y = p\%\times a$, where $p\% = 0.8$ and $a = 20$, we have $y=0.8\times20 = 16$ problems.

Step8: Solve problem 7

There are 36 carpenters and 29 showed up. Using the formula $\frac{a}{b}\times100\%$, we get $\frac{29}{36}\times100\%=\frac{2900}{36}\approx 80.56\%$.

Step9: Solve problem 8

A metal bar weighs 8.15 ounces and 93% (or 0.93 as a decimal) is silver. Using the formula $y=p\%\times a$, we have $y = 0.93\times8.15=7.58$ ounces.

Step10: Solve problem 9

The original price of the car is $7200$ and Bob bought it for 65% (or 0.65 as a decimal) of the original price. Using the formula $y=p\%\times a$, we get $y=0.65\times7200 = 4680$.

Step11: Solve problem 10

Pamela paid $32.89$ for a drill which is 85% (or 0.85 as a decimal) of the regular price. Using the formula $x=\frac{y}{p\%}$, we have $x=\frac{32.89}{0.85}=38.69$.

Answer:

1. Approximately 17.46%
2. Approximately 18.23%
3. 144.03
4. 141.6
5. Approximately 78.90%
6. 16 problems
7. Approximately 80.56%
8. 7.58 ounces
9. $4680
10. $38.69