Number System Questions

Multiple choice
  1. 140n + 2

  2. 160n + 2

  3. 180n + 2

  4. 200n + 2

  5. 220n + 2

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

The number must leave a remainder of 2 when divided by 3, 4, and 5. This means the number must be of the form LCM(3, 4, 5) * n + 2. LCM(3, 4, 5) = 60. Thus, the form is 60n + 2. Since 180n is a multiple of 60, 180n + 2 also satisfies the condition.

Multiple choice
  1. 1012

  2. 1201

  3. 1212

  4. 1210

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

Two-digit numbers leaving a remainder of 1 when divided by 4 follow the sequence 13, 17, 21, ..., 97. This is an arithmetic progression with first term a=13, last term l=97, and common difference d=4. The number of terms n is (97-13)/4 + 1 = 22. The sum is (n/2)(a+l) = (22/2)(13+97) = 11 * 110 = 1210.