Support Reactions of a Trapezoidal Slab with Three Points of Support

Situation
A reinforced concrete slab in the shape of an isosceles trapezoid weighs 3600 N/m2. It is supported on the three points as shown in the figure.
 

eq-parallel-forces-trapezoid-slab.gif
  1. Find the reaction at A.
    A.   16,848 N
    B.   6,716 N
    C.   13,372 N
    D.   2,010 N
  2. Find the reaction at B.
    A.   16,848 N
    B.   6,716 N
    C.   13,372 N
    D.   2,010 N
  3. Find the reaction at C.
    A.   16,848 N
    B.   6,716 N
    C.   13,372 N
    D.   2,010 N

 

Equation of the Locus of a Moving Point

Definition of a Locus
Locus is a Latin word which means "place". In mathematics, locus is the set of points that satisfies the same geometrical properties. In most cases, the relationship of these points is defined according to their position in rectangular coordinates.
 

Example 1
Determine the equation of the curve such that the sum of the distances of any point of the curve from two points whose coordinates are (-3, 0) and (3, 0) is always equal to 8.
    A.   4x2 + 49y2 - 343 = 0
    B.   7x2 + 16y2 - 112 = 0
    C.   7x2 - 16y2 + 112 = 0
    D.   4x2 - 49y2 + 343 = 0
 

01 - Example of Mixture Related Problem

Problem
In a class experiment, a student needs 5 liters of 6% solution. He found a 4% and a 10% solution in the laboratory. How many liters of each solution should he mix in order to obtain 5 liters of 6% solution?
A. 3.33 liters of 4% and 1.67 liters of 10% solution
B. 1.67 liters of 4% and 3.33 liters of 10% solution
C. 3.67 liters of 4% and 1.33 liters of 10% solution
D. 1.33 liters of 4% and 3.67 liters of 10% solution