Practice Exams ChE - 25

1. The cost of a product is a function of the quantity x of the product is given by the relation C(x) = x^2 - 40000x + 50. Find the quantity for which the cost is minimum.
a. 1000
b. 2000
c. 15000
d. 3000
e. none of the above

2. When all odd numbers from 1 to 101 is added, what will be the sum?
a. 2500
b. 2601
c. 2510
d. 5601
e. none of the above

3. If y = x/2 + [sin(2x)]/4; find x for which dy/dx = 0.
a. Pi/4
b. Pi/2
c. Pi/3
d. Pi/6
e. Pi/12

4. Which of the following is not factorable?
a. 2m^2 + mn + 3n^2
b. –x^2 – x + 12
c. s^12 – 1
d. t^2 + 25
e. none of the above

5. A tank contains 100 gal water. A salt solution containing 2 lb salt per gal flows in at a rate of 3 gpm and well-stirred tank flows out at the same rate. The concentration of the solution inside the tank after 1 hr is
a. 11 lb/gal
b. 1.18 lb/gal
c. 1.18 lb
d. 1.8 lb/gal
e. none of the above

6. 75 students went to SM West where they could watch 3 films (A, B, & C). 20 of them watched all 3 films. 55 of them watched at least 2 films. Because it was QC day, each film cost only P5.00 per head. If the total receipt was P700, how many students did not watch any movie?
a. 9
b. 11
c. 10
d. 12
e. none of the above

7. What is the value of x for which y = 2x^3 – 3x^2 – 36x +25 will have an inflection point?
a. 1/3
b. ¼
c. ½
d. 1/5
e. 2/3

8. A steel rod is stretched between 2 rigid walls and carries a tensile load of 5000 N at 20 degC. What T will the stress be zero? The cross-sectional area is 150 mm2.
a. 34.2 degC
b. 45.5 degC
c. 30.0 degC
d. 42.9 degC
e. none of the above

9. The locus of a point that move so that its distance from fixed point and fixed line is always equal is known as:
a. parabola
b. hyperbola
c. ellipse
d. circle

10. The area of a triangle are formed by points A(4,-3), B(7,4), C(-3,6) is
a. 28 sq units
b. 38 sq units
c. 48 sq units
d. 58 sq units
e. none of the above