Averages Questions

Multiple choice
  1. 29.75

  2. 30.50

  3. 31.25

  4. 32.50

  5. 33.75

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

Let A, D, G, J be the number of sweets. (i) A = G/3. (ii) (J+D)/2 = 27 => J+D = 54. (iii) (G+J+D)/3 = 30 => G+54 = 90 => G = 36. Then A = 12. Total sweets = 12+36+54 = 102. Radha gives 5 sweets to each of the 4 friends, adding 20 sweets. New total = 122. Average = 122/4 = 30.5.

Multiple choice
  1. 3 : 2

  2. 2 : 3

  3. 1 : 3

  4. 3 : 1

  5. a

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

Let N1 be the number of old boxes with average weight A1, and N2 be the number of new boxes with average weight A2 = A1 + 2. The new average is (N1*A1 + N2*(A1+2)) / (N1+N2) = A1 + 0.8. N1*A1 + N2*A1 + 2*N2 = (A1 + 0.8)(N1 + N2) = N1*A1 + N1*0.8 + N2*A1 + N2*0.8. 2*N2 = 0.8*N1 + 0.8*N2. 1.2*N2 = 0.8*N1. N1/N2 = 1.2/0.8 = 3/2.

Multiple choice
  1. 19

  2. -19

  3. -21

  4. 21

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

Let S be the sum of 40 integers. Average = S/40. Sum of remaining 39 = S - a1. Average of remaining = (S - a1)/39. Given S/40 = (S - a1)/39 - 3. Solving for a1 with a40=120 and the increasing order constraint leads to a1 = -19.

Multiple choice
  1. 90,000

  2. 80,000

  3. 95,000

  4. 85,000

Reveal answer Fill a bubble to check yourself
C Correct answer
Multiple choice
  1. 1.0

  2. 1.5

  3. 2.0

  4. 2.5

  5. 3.0

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

Let initial sum be S, number of people = 4. Average = S/4. (S+T)/5 = S/4 - y. (S+U)/5 = S/4 + 3y. Subtracting: (U-T)/5 = 4y. Given U-T = 40, so 40/5 = 4y. 8 = 4y, so y = 2.

Multiple choice
  1. 38.44

  2. 34.88

  3. 33.84

  4. 32.48

  5. a

Reveal answer Fill a bubble to check yourself
C Correct answer