Quantitative Aptitude - Numbers and Algebra
- Option : B
- Explanation : Number of members in C1 on May 1, 2012 = x + 4ya
Number of members in C2 on May 1, 2012= xb4
x + 4a = xb4 and a = 20x
∴ x(b4 - 81)
As x ≠ 0, b4 - 81 = 0
∴ b = 3
32. Which of the following is true?
- Option : D
- Explanation :
(√2+√5)² = 2 + 2√10 +5 =7+2√10
(√7)² = 7
∴ √2+√5> 7
Alternatively:
√2 > √1 and √5 > √4
∴ √2+√5 > 2+1
=> √2 + √5 > 3 and √7 < √9 = 3
=> √7 < 3.
so √2 + √5>√7
- Option : B
- Explanation :
L.C.M. of 5, 6, 8, 9 and 12 is 360
Required number = 360 K + 1 = (13 x 27 + 9) K + 1
= (13 x 27) K + (9K + 1)
Now this number must be divisible by 13 K = 10 and required number = 3601.
- Option : C
- Explanation :
Total marks of 15 students = 15 x 145 = 2175.
Average marks of 15 students (excluding two lowest scores) = 13 x (145 + 5) = 1950.
∴ Total of two lowest scores = 2175 1950 = 225
Given that two scores are consecutive multiples of 9 * 9x + 9x + 9 = 225 18x = 216
=> 18/x = 216 => x = 216/18
Lowest score = 9x = (216/18) x 9 = 108
- Option : A
- Explanation :
Number is 120K + 1= ((13 * 9 + 3) K + 1)
= 13 * 9K + 3 K + 1, which is divisible by 13.
3K + 1 is divisible by 13.
∴ K = 4. Number = 481
