Number System Questions

Multiple choice
  1. 18

  2. 48

  3. 48, 78

  4. 10, 48, 78

  5. 12, 42, 72

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Given 5m = 84k + 30, we can divide by 5 to get m = 16.8k + 6. Since m is an integer, k must be a multiple of 5, say k = 5n. Then m = 84n + 6. We want to find the remainder of 8m when divided by 84. Substituting m, 8m = 8(84n + 6) = 672n + 48. Since 672 is a multiple of 84 (84 * 8 = 672), 8m = 84(8n) + 48. The remainder is 48.

Multiple choice
  1. p & q Only

  2. p, r & s Only

  3. q, r & s Only

  4. r & s Only

  5. p, q & r Only

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

B is the largest root of w^2 - 6w + 8 = 0, which factors to (w-4)(w-2)=0, so B=4. A is HCF of two primes, which is 1. Substituting: p = (1+3)^2 + 4 + 5 = 25; q = (1+2)^2 + 4 + 25 = 38; r = (1+4)^2 + 4 + 38 = 67; s = (1+5)^2 + 4 + 67 = 107. Numbers not divisible by 5 are q, r, and s.

Multiple choice
  1. 17004

  2. 18000

  3. 18002

  4. 18004

  5. 19000

Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

LCM(16, 18, 20, 25) = 3600. The number is 3600k + 4. Testing multiples: 3600*5 + 4 = 18004. 18004 / 7 = 2572 with remainder 0. So 18004 is the number.