# Examples for secondary school students - page 77

1. Air thermal Imagine that a unit of air rises at 3000 meters high, if temperature decreases 6 degrees celcius for every 1000 meter, what will be its temperature at 1400 meters, 2000 meters, 2500 meters and when it reaches the 3000 meter elevation. Starting temperature.
2. Percent change If the length of a rectangle is increased by 25% and the width is decreased by 10%, the area of the rectangle is larger than the area of the original rectangle by what percent?
3. Triangle 42 Triangle BCA. Angles A=119° B=(3y+14) C=4y. What is measure of triangle BCA=?
4. Mixed with percentages Calculate 33 1/3% of 570.
5. Completing square Solve the quadratic equation: m2=4m+20 using completing the square method
6. Election 4 In a certain election there are 3 candidates for president 5 for secretory and 2 for tresurer. Find how many ways the election may (turn out/held).
7. Shuyen Shuyen wanted to save some money. She deposited Php.300 in a bank which pays 0.5% interest per annum. After nine months, she needed the money to buy some gifts. How much will she be able to get if he withdraws all her money from the bank?
8. A screen A screen is 1680 x 1050 pixels. What are the coordinates (and size in pixels) of an centered area which is exactly 33% of the screen size?
9. Right 24 Right isosceles triangle has an altitude x drawn from the right angle to the hypotenuse dividing it into 2 unequal segments. The length of one segment is 5 cm. What is the area of the triangle? Thank you.
10. A student A student is to answer 8 out of 10 questions on the exam. a) find the number n of ways the student can choose 8 out of 10 questions b) find n if the student must answer the first three questions c) How many if he must answer at least 4 of the first 5 que
11. Eq with reciprocal Solve given equation with reciprocal member: a-6/a+10=4/8
12. Substitution method Solve goniometric equation: sin4 θ - 1/cos2 θ=cos2 θ - 2
13. Coordinates of vector Determine the coordinate of a vector u=CD if C(19;-7) and D(-16;-5)
14. Normal distribution GPA The average GPA is 2.78 with a standard deviation of 4.5. What are students in the bottom the 20% having what GPA?
15. The size The size of a Trapezium are 3/4×cm, ×cm 2(×+1)cm and 3(×+2)cm long respectively if it's perimeter is 60cm, calculate the length of each side.
16. Degrees Fahrenheit ? The equation above shows how temperature F, measured in degrees Fahrenheit, relates to a temperature C, measured in degrees Celsius. Based on the equation, which of the following must be true? I. A temperature increase of 1 degree Fahrenheit is equiv
17. Annular area The square with side a = 1 is inscribed and circumscribed by circles. Find the annular area.
18. Lateral surface area The ratio of the area of the base of the rotary cone to its lateral surface area is 3: 5. Calculate the surface and volume of the cone, if its height v = 4 cm.
19. The position The position of a body at any time T is given by the displacement function S=t3-2t2-4t-8. Find its acceleration at each instant time when the velocity is zero.
20. Component fail There is a 90 percent chance that a particular type of component will perform adequately under high temperature conditions. If the device involved has four such components, determine the probability that the device is inoperable because exactly one of the.

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