Mathematics
Average / Arithmetic Mean
A family of 8 people has average age 35. After 5 years, a relative aged 25 at that future time joins them. What is the new average then?
A. 40.33 years
B. 37.33 years
C. 39.33 years
D. 38.33 years
Correct Answer: D
Future total of original members = 8×(35+5); add 25 and divide by 9.
Mathematics
Average / Arithmetic Mean
A family of 7 people has average age 34. After 4 years, a relative aged 24 at that future time joins them. What is the new average then?
A. 36.25 years
B. 35.25 years
C. 37.25 years
D. 38.25 years
Correct Answer: A
Future total of original members = 7×(34+4); add 24 and divide by 8.
Mathematics
Average / Arithmetic Mean
A family of 6 people has average age 33. After 3 years, a relative aged 23 at that future time joins them. What is the new average then?
A. 33.14 years
B. 34.14 years
C. 36.14 years
D. 35.14 years
Correct Answer: B
Future total of original members = 6×(33+3); add 23 and divide by 7.
Mathematics
Average / Arithmetic Mean
A family of 5 people has average age 32. After 2 years, a relative aged 22 at that future time joins them. What is the new average then?
A. 34 years
B. 33 years
C. 32 years
D. 31 years
Correct Answer: C
Future total of original members = 5×(32+2); add 22 and divide by 6.
Mathematics
Average / Arithmetic Mean
A family of 8 people has average age 31. After 5 years, a relative aged 21 at that future time joins them. What is the new average then?
A. 36.33 years
B. 33.33 years
C. 35.33 years
D. 34.33 years
Correct Answer: D
Future total of original members = 8×(31+5); add 21 and divide by 9.
Mathematics
Average / Arithmetic Mean
A family of 7 people has average age 30. After 4 years, a relative aged 20 at that future time joins them. What is the new average then?
A. 33.25 years
B. 31.25 years
C. 34.25 years
D. 32.25 years
Correct Answer: D
Future total of original members = 7×(30+4); add 20 and divide by 8.
Mathematics
Average / Arithmetic Mean
A family of 6 people has average age 29. After 3 years, a relative aged 19 at that future time joins them. What is the new average then?
A. 31.14 years
B. 32.14 years
C. 29.14 years
D. 30.14 years
Correct Answer: D
Future total of original members = 6×(29+3); add 19 and divide by 7.
Mathematics
Average / Arithmetic Mean
A family of 5 people has average age 28. After 2 years, a relative aged 18 at that future time joins them. What is the new average then?
A. 29 years
B. 30 years
C. 28 years
D. 27 years
Correct Answer: C
Future total of original members = 5×(28+2); add 18 and divide by 6.
Mathematics
Average / Arithmetic Mean
The average age of 29 students is 18 years. Including a teacher aged 44 years, what is the new average age?
A. 18.87 years
B. 20.87 years
C. 17.87 years
D. 19.87 years
Correct Answer: A
New mean = (29×18+44)/30 = 18.87 years.
Mathematics
Average / Arithmetic Mean
The average age of 28 students is 17 years. Including a teacher aged 43 years, what is the new average age?
A. 17.9 years
B. 16.9 years
C. 19.9 years
D. 18.9 years
Correct Answer: A
New mean = (28×17+43)/29 = 17.9 years.
Mathematics
Average / Arithmetic Mean
The average age of 27 students is 16 years. Including a teacher aged 42 years, what is the new average age?
A. 18.93 years
B. 16.93 years
C. 15.93 years
D. 17.93 years
Correct Answer: B
New mean = (27×16+42)/28 = 16.93 years.
Mathematics
Average / Arithmetic Mean
The average age of 26 students is 15 years. Including a teacher aged 41 years, what is the new average age?
A. 16.96 years
B. 14.96 years
C. 17.96 years
D. 15.96 years
Correct Answer: D
New mean = (26×15+41)/27 = 15.96 years.
Mathematics
Average / Arithmetic Mean
The average age of 25 students is 14 years. Including a teacher aged 40 years, what is the new average age?
A. 17 years
B. 16 years
C. 14 years
D. 15 years
Correct Answer: D
New mean = (25×14+40)/26 = 15 years.
Mathematics
Average / Arithmetic Mean
The average age of 24 students is 18 years. Including a teacher aged 39 years, what is the new average age?
A. 20.84 years
B. 19.84 years
C. 18.84 years
D. 17.84 years
Correct Answer: C
New mean = (24×18+39)/25 = 18.84 years.
Mathematics
Average / Arithmetic Mean
The average age of 23 students is 17 years. Including a teacher aged 38 years, what is the new average age?
A. 18.88 years
B. 16.88 years
C. 17.88 years
D. 19.88 years
Correct Answer: C
New mean = (23×17+38)/24 = 17.88 years.
Mathematics
Average / Arithmetic Mean
The average age of 22 students is 16 years. Including a teacher aged 37 years, what is the new average age?
A. 17.91 years
B. 18.91 years
C. 16.91 years
D. 15.91 years
Correct Answer: C
New mean = (22×16+37)/23 = 16.91 years.
Mathematics
Average / Arithmetic Mean
The average age of 21 students is 15 years. Including a teacher aged 36 years, what is the new average age?
A. 14.95 years
B. 15.95 years
C. 16.95 years
D. 17.95 years
Correct Answer: B
New mean = (21×15+36)/22 = 15.95 years.
Mathematics
Average / Arithmetic Mean
The average age of 20 students is 14 years. Including a teacher aged 35 years, what is the new average age?
A. 17 years
B. 16 years
C. 14 years
D. 15 years
Correct Answer: D
New mean = (20×14+35)/21 = 15 years.
Mathematics
Average / Arithmetic Mean
A section of 24 members has mean 44. Another section of 8 members with mean 64 is merged into it. What is the resulting mean?
A. 48
B. 50
C. 49
D. 51
Correct Answer: C
Resulting mean = (24×44+8×64)/32 = 49.
Mathematics
Average / Arithmetic Mean
A section of 23 members has mean 43. Another section of 7 members with mean 63 is merged into it. What is the resulting mean?
A. 47.67
B. 48.67
C. 49.67
D. 46.67
Correct Answer: A
Resulting mean = (23×43+7×63)/30 = 47.67.