The number of minutes in a week is:

$\displaystyle 24\ hrs./day \times 60\ min./hr. \times 7\ days/week = 10,080 \ min./week$

The number of minutes spent studying is:

$\displaystyle (90\ min./day \times 5) + (120\ min./day \times 2) = 690$

$\displaystyle 690/10080 = .68 \times 100 = 6.8$

6.8%

Percentage = Students on Soccer Team / Total Number of Students

= 3/8 = .375 = 37.5%

There are three students involved in soccer.  Read across the chart and two of them are also involved in newspaper.

Percentage = 2/Total Number of Students

= 2/8 = .25 = 25%

This problem requires simple arithmetic, 30% of 93 can be obtained by multiply 93 X .30 = 27.9 Rounding yields 28 years.

8,100 * 0.09 = 729

Subtract 3, 26, and 31 from 76 to figure out how many students got A's (16). 

$\displaystyle \dpi{100} \small \frac{16}{76} \times 100$

To find the percentage of a number, convert the percentage into a decimal by diving the percent by 100.

$\displaystyle \frac{73}{100} = 0.73$,

then multiply that decimal by the number. 

$\displaystyle 225\cdot 0.73 = 164.25$

For percentage problems, the easiest way to start is by remembering that the word "of" is best translated as a multiplication, while the word "is" is best translated by an equals sign. Thus, for the information provided, we can write the equation:

$\displaystyle \small 15 = x * 48$

Remember, though, that $\displaystyle \small x$ will represent a percentage in a decimal form and will need to be translated. (There are other ways of doing this, but most students remember to do this translation at the end naturally.)

Solving for $\displaystyle x$, you get:

$\displaystyle \small x=\frac{15}{48}=0.3125$

This is $\displaystyle \small 31.25\%$.

For percentage problems, the easiest way to start is by remembering that the word "of" is best translated as a multiplication, while the word "is" is best translated by an equals sign. Thus, for the information provided, we can write the equation:

$\displaystyle \small x = 0.3 * 0.52*1837$

Solving for $\displaystyle x$, you get:

$\displaystyle \small \small x = 286.572$

Alternatively you could first calculate $\displaystyle 52\%$ of $\displaystyle 1837$, which is $\displaystyle 955.24$, and then calculate $\displaystyle 30\%$ of that, and you would arrive at the same answer.

The most common way to do a problem like this is to begin by applying the first discount, calculating the amount to be removed from the original price. This is done by multiplying the original price by $\displaystyle \small 0.3$. This gives you $\displaystyle 551.1$. This is then subtracted from $\displaystyle \small 1837$ to give you $\displaystyle \small 1285.9$. Once again, this new number is multiplied, now by $\displaystyle \small 0.25$. This gives you $\displaystyle \small 321.475$. When subtracted from $\displaystyle \small 1285.9$, this gives you a final price of $\displaystyle \small 964.425$, or the rounded value of $\displaystyle \small \small 964.43$.

A simpler way to do this is to realize that the first price reduction makes the new price to be $\displaystyle \small 70\%$ of the original. The second will then make the price to be $\displaystyle \small 75\%$ of the intermediary price. Thus, you could easily compute:

$\displaystyle \small \small 1837 * 0.7 * 0.75 = 964.425$