CAT 2001



Ans .

(c) 4


  1. Explanation :

    Let the marks scored in five subjects be 6x, 7x, 8x, 9x and 10x (on a scale of 1). Average score = 60% ⇒\(\frac{6x+7x+8x+9x+10x}{5}\)= \( \frac{60}{100} \)⇒ 8x = 0.6 ⇒ x = 0.075
    So the marks are 0.45, 0.525, 0.6, 0.675 and 0.75. Number of times the marks exceed 50% is 4.





Ans .

(b)


  1. Explanation :

    Smiley face
    Let the length of the edge cut at each corner be x m. Since the resulting figure is a regular octagon,

    Smiley face





Ans .

(a)


  1. Explanation :

    Check the answer choices basis the fact that: Odd × Odd = Odd Odd × Even = Even Even × Even = Even





Ans .

(d)


  1. Explanation :

    x > 5, y < –1 Use answer choices. Take x = 6, y = –6. We see none of the statements (a), (b) and (c) is true.
    Hence the correct option is (d).





Ans .

(a)


  1. Explanation :

    First light blinks after 20 s. Second light blinks after 24 s.
    They blink together after LCM (20 and 24) = 120 s = 2 min. Hence, the number of times they blink together in an hour = 30





Ans .

(c)


  1. Explanation :

    We can put a minimum of 120 oranges and a maximum of 144 oranges, i.e., 25 oranges need to be filled in 128 boxes. There are 25 different possibilities if there are 26 boxes.
    In such a case, at least 2 boxes contain the same number of oranges. (i.e., even if each of the 25 boxes contain a different number of oranges, the 26th must contain one of these numbers).
    Similarly, if there are 51 boxes, at least 3 boxes contain the same number of oranges. Hence, at least 6 boxes have the same number of oranges in case of 128 boxes.





Ans .

(b)


  1. Explanation :

    Smiley face
    ∆APS and ∆AOC are similar triangles. Where OC = r
    \( \frac{r}{r+3} \) = \( \frac{9}{√(81 (2r+3)2} \)
    Now use the options. Hence, the diameter is 9 km.