Reviewer Page Guides

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159

Civil Service Commission Professional or Sub-Professional Reviewer - Page 116/159

Mathematics Test V Solution - Page 116

46. If 8 men can plant 288 trees in one day, how many trees can 12 men plant in 5 days?

Let N - be the number of trees

N =       288 trees    x 12 men x 5 days    ----->  288 x 12 x 5
        8 men - 1 day                                                   8          trees

N = 2, 160 trees * Ans.


47. If the length of a rectangle is increased by 25% and its width is decreased by 20%, what happens to the area of the triangle?

Aorig. = LW

Anew = L (1+0.25) x W (1 - 0.20)
         = L (1.25) x W (0.8)              -----> (1.25) (0.8) LW
Anew = 1 x LW
Anew = Aorig.

therefore, no change in the area * Ans.

48. The formula for the volume of a sphere is V = 4/3 πr3. If the radius (r) is tripled, what will be the ratio of the new volume to the original volume?

Vorig. = 4/3 πr3

Vnew = 4/3 π(3r)3              ----->   = 4/3 π(27r3)        ------> 27 (4/3  πr3)
Vnew = 27 Vorig.                ----->   Vnew : Vorig.   =  27 : 1 * Ans.

49. The scale on a map is 1 : 8. If a surveyor reads a certain measurement on the map as 4.6 cm instead of 5.0 cm, what will be the resulting approximate percent error on the full size model?

% error =   error   x 100% ->   5.0 - 4.6  x 100% -> 0.4 x 100% -> 8% *Ans.
              correct value                  5.0                                5

50. In a certain recipe, 225 grams of beef are called for to make 6 servings. If Mrs. Alferez wants to use the recipe for 8 servings, how many grams of beef must she use?

Let N - be the number of grams required

225 : 6 = N : 8

6N = 8(225)
6N = 1800
N   = 1800 / 6
N   = 300 grams. * Ans.

Civil Service Reviewer Post 116/159