Secant cannot be equal to 1/sine, as stated. Secant is equal to 1/cosine, where cosine is the hypotenuse or neighboring side of a right triangle.
You must determine the difference of 2,460 in a percentage of a half. To perform this mentally, first calculate 1 percent of the starting value, then divide that by 2. 1% of 2,460 in this instance equals 24.6, and half of that is 12.3. We may calculate the population increase as 12 individuals since you cannot have 3/10 of a person. The new population is 2,472 when that is added to the initial 2,460.
In a game where the dealer keeps the gambler's bet if he draws any card other than a club or queen, his chances of winning the money are 38% better than the gambler's. A deck of cards has 52 cards, with 13 cards in each suit, including clubs. Each deck has four queens, but since the queen of clubs has already been tallied, the gambler's list of winning cards only includes the queens of hearts, diamonds, and spades. The gambler's odds of winning are 31% because he must draw one of the 16 cards to succeed. If his odds are 31%, the gambler has far better odds of 69%, which is an improvement of 38%.
168 softballs. Although this is not a difficult problem and could be calculated mentally, perhaps by multiplying 14 by 10 (140), then adding 2 more 12s to the answer.
However, there is a trick that allows you to multiply numbers close to ten together within seconds.
First, consider the problem: 14 x 12
Using the 2 in 12, add it to 14: 16 (these are the first two digits of the answer).
Using the 2 in 12, multiply it by the 4 in 14: 8 (this is the last digit of the answer).
Thus, the answer to 14 x 12 is 168.
It works for larger numbers in the teens, but those involve “carrying”.
Consider the problem: 17 x 14.
Using the 4 in 14, add it to 17: 21
Using the 4 in 14, multiply it by the 7 in 17 (28). The 8 is the last digit of the answer. Carry the 2 over, and add it to the 21 from the previous step to get 23.
The answer to 17 x 14 is 238.
To find 25% of a given number, simply halve the number, then halve it again. In this example, half of 460,000 is 230,000, then half of 230,000 is 115,000. Therefore, 25% of $460,000 is $115,000. Add $115,000 to the original $460,000 to find the gross revenue for the year - $575,000.
The ability to estimate and round figures is essential for answering inquiries as fast as feasible.
Take some time to carefully select your numbers before coming up with your solution. Choose rounded numbers that go well together and will make your math much easier.
The quickest way to do this problem is to divde 60 by 200.
You can quickly reduce that to 3/10. Then multiply 3/10 by 60 to get 18 minutes.
$571,000. $4 million divided by 7 days is an average of $571,429 per day.
First, calculate the dollar value of the markdown: 29,600 – 22,100 = 7,500. The result is 0.2533 when you divide the total reduction of $7,500 by the original price of $29,600. To find out that the markdown is somewhat more than 25%, move the decimal point two places to the right.
Theoretically, an observation's weight is defined as having an inverse relationship to its variance. Accordingly, the observation should be given more weight because it will be more exact and precise with a reduced observation error.
Use the Rule of 72 to mentally compute the result.
72 divided by the growth rate. In this case, Paul's wealth would increase by twofold in eight years (72/9). An easy method for estimating how long it would take for an investment to double in value is the rule of 72.
