General Mathematics

Question: Three years ago, the average age of A ,B and C was `27` year and that of B and C, `5` years .A ,s present age is :
A
`30 yrs`

B
`35 yrs`

C
`40 yrs`

D
`48 yrs`

Note: present ago of ( A + B + C) `= (27 xx 3 + 3 xx 3)` `= 90 years` present ago of (B + C) `= (20 xx 2 + 2 xx 5)` `= 50 years` `:. A,s present age `= (90 - 50) years` `= 40 years`
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Question: Three years ago, the average age of a family of `5` members was `17` years .A baby having been born ,the average age of the family is the same today. The present age of the baby is :
A
`2 yrs`

B
`2.4 yrs`

C
`3 yrs`

D
`1.5 yrs`

Note: Total age of `5` members, `3` years ago `= (17 xx 5)` Total age of `5`members now `= (85 + 3 xx 5)` `= 100 years` Total age of members now `= (17 xx 6)` `= 102 years` Age of the baby `= 2 years`
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Question: Five years ago, the average age of A,B,C and D was `45` years .With E joing them now, the average of all the five is `49`.How old is E ?
A
`25 yrs`

B
`40 yrs`

C
`45 yrs`

D
`64 yrs

Note: (A + B + C + D),five years ago `= (45 xx 4)` `= 180 years` (A + B + C + D), now `= (180 + 5 xx 4) years` `= 200 years` A + B + C + D + E, now `= (49 xx 5) years` `= 245 years` :. E, now `= (245 - 200)` `= 45 years`
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Question: Five years ago, The average age of Q was `15` years. A average age of P,Q and R today is `20` years. How old will R be after `10` years ?
A
`35 years`

B
`40 years`

C
`30 years`

D
`50 years`

Note: (P + Q),five years ago `= (15 xx 2)` `= 30 years` (P + Q), now `= (30 + xx 2) years` `= 40 years` (P + Q + R),now `= (20 xx 3) years` `= 60 years` :. R now `= (60 - 40) years` `= 20 years` R, after `10` years `= (20 + 10) years` `= 30 years`
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Question: The average age of boys in the class is twice the number of girls in the class.If the ratio of boys and girls in the class of `36` be `5 : 1`,what is the total of the ages (in years) of the boys in the class ?
A
`490`

B
`196`

C
`420`

D
`360`

Note: Number of boys `= (36 xx 5/6) = 30` Number of girls `= 6` A average age of boys `= (2 xx 6) = 12 years` :. Total age of boys `= (30 xx 12) years` `= 360 years`
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Question: In a cricket eleven ,the average of eleven players is `28` years.Out of these, the average ages of three groups of three players each are `25` years, `28`years and `30`years respectively.If in these groups, the captain and the youngest player are not included, and the captain and the youngest player, what is the age of the captain ?
A
`33 years`

B
`34 years`

C
`35 years`

D
`36 years`

Note: Let the age of youngest player be x. Then, age of the captain `= (x + 11)` `:. 3 xx 25 + 3 xx 28 + 3 xx 30 + x + x + 11` `= 11 xx 28` `⇒ 75 + 84 + 90 + 2x + 11` `= 308 ⇒ 2x = 48` `⇒ x = 24`. :. Age of the captain `= (x + 11)` `= 35 years`
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Question: After replacing an old member by anew member, it was found that the average age of five members of a club is the same as it was `3` years ago. What is the difference between the ages of the replaced and the new mwmber ?
A
`15 yrs`

B
`8 yrs`

C
`4 yrs`

D
`2 yrs`

Note: Age decreased `= (5 xx 3) years` `= 15 years` So, the required difference `= 15 years`
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Question: The average age of a class is `15.8 years`The average age of the boys in the class is `16.4 years` while that of the girls is `15.4 years.What is the ratio of boys to girls in the class
A
`1 : 2`

B
`3 : 4`

C
`3 : 5`

D
None of these

Note: Let the ratio be` k : 1`.Then `k xx 16.4 + 1 xx 15.4` `= (k + 1) xx 15.8` `or (16.4 - 15.8) k` `= (15.8 - 15.4)` `or k = 0.4/0.6` `= 2/3` :. Required ratio `= 2/3 : 1` `= 2 : 3`.
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Question: The average age of `3` children in a family is `20‰` of the average age of the father and the eldest child. The total age of the mother and the youngest child is `39` years. If the father,s age is `26` years, what is the age of second child ?
A
`15 yrs`

B
`18 yrs`

C
`20 yrs`

D
Can not be determined

Note: Since the total or average age of all the famial members is not given, the given data is inadequate .So the age of second child cannot be determind.
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Question: At the rate of 6% p.a.simple interest ,a sum of Rs.`2500` will earn how much interest by the end of `5` years ?
A
`Rs 150`

B
`Rs 700`

C
`Rs 750`

D
`Rs 3250`

Note: s.I = Rs `(2500 xx 6 xx 5/100)` `= Rs 750`
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Question: Three years ago, the average age of A ,B and C was `27` year and that of B and C, `5` years .A ,s present age is :

Question: Three years ago, the average age of a family of `5` members was `17` years .A baby having been born ,the average age of the family is the same today. The present age of the baby is :

Question: Five years ago, the average age of A,B,C and D was `45` years .With E joing them now, the average of all the five is `49`.How old is E ?

Question: Five years ago, The average age of Q was `15` years. A average age of P,Q and R today is `20` years. How old will R be after `10` years ?

Question: The average age of boys in the class is twice the number of girls in the class.If the ratio of boys and girls in the class of `36` be `5 : 1`,what is the total of the ages (in years) of the boys in the class ?

Question: After replacing an old member by anew member, it was found that the average age of five members of a club is the same as it was `3` years ago. What is the difference between the ages of the replaced and the new mwmber ?

Question: The average age of a class is `15.8 years`The average age of the boys in the class is `16.4 years` while that of the girls is `15.4 years.What is the ratio of boys to girls in the class

Question: The average age of `3` children in a family is `20‰` of the average age of the father and the eldest child. The total age of the mother and the youngest child is `39` years. If the father,s age is `26` years, what is the age of second child ?

Question: At the rate of 6% p.a.simple interest ,a sum of Rs.`2500` will earn how much interest by the end of `5` years ?