The average age of 80 boys in a class is 15. The average age of group of 15 boys in the class is 16 and the average of another 25 boys in the class is 14. What is the average age of the remaining boys in the class ?

Severity: Warning

Message: Undefined property: stdClass::$answer

Filename: questions/index.php

Line Number: 181

Backtrace:

File: /var/www/html/application/views/questions/index.php

Line: 181

Function: _error_handler

File: /var/www/html/application/controllers/Questions.php

Line: 121

Function: view

File: /var/www/html/index.php

Line: 315

Function: require_once

otal ages of 80 boys = 15 x 80 = 1200 yrs.

Total age of 16 boys = 15 x 16 = 240 yrs

Total age of 25 boys = 14 x 25 = 350 yrs.

Average age of remaining boys = \(1200 - \frac{240+350}{80}-\left ( 25+15 \right )\)= \(\frac{610}{41}\)

= 15.25 yearss

A is three times as old as B. C was twice-as old as A four years ago. In four years' time, A will be 31. What are the present ages of B and C ?

Severity: Warning

Message: Undefined property: stdClass::$answer

Filename: questions/index.php

Line Number: 181

Backtrace:

File: /var/www/html/application/views/questions/index.php

Line: 181

Function: _error_handler

File: /var/www/html/application/controllers/Questions.php

Line: 121

Function: view

File: /var/www/html/index.php

Line: 315

Function: require_once

Let the age of A = \(A\), B = \(B\) and C = \(C\)

From given,

\(A = 3B\)

4 years ago,

\(A + 4 = 31\)

\(\Rightarrow A=27\)

sub in above \(B\) , we get \(B\) = 9

\(C = 2(27 - 4) + 4 = 46 + 4 = 50 \)

Hence B = 9years and C = 50years.

Today is Varun's birthday. One year, from today he will be twice as old as he was 12 years ago. How old is Varun today ?

Severity: Warning

Message: Undefined property: stdClass::$answer

Filename: questions/index.php

Line Number: 181

Backtrace:

File: /var/www/html/application/views/questions/index.php

Line: 181

Function: _error_handler

File: /var/www/html/application/controllers/Questions.php

Line: 121

Function: view

File: /var/www/html/index.php

Line: 315

Function: require_once

Let varun's age = \(x\) years.

From the given conditions,

\(\Rightarrow x+1 = 2(x-12)\)

\(\Rightarrow x=25\) years.

The sum of the ages of 5 children born at the intervals of 3 years each is 50 years. What is the age of the youngest child ?

Severity: Warning

Message: Undefined property: stdClass::$answer

Filename: questions/index.php

Line Number: 181

Backtrace:

File: /var/www/html/application/views/questions/index.php

Line: 181

Function: _error_handler

File: /var/www/html/application/controllers/Questions.php

Line: 121

Function: view

File: /var/www/html/index.php

Line: 315

Function: require_once

Let the age of the youngest child is '\(x \)' years.

Then the child elder than the yongest is '\(x + 3\)' yrs

Since each have 3yrs difference upto 5 children

And given that,

\(\Rightarrow x +x +3 + x+6 +x+9 + x+12 = 50\)

\(\Rightarrow 5x+30=50\)

\(\Rightarrow x= 4\) years.

Rajan's present age is three times his daughter's and nine-thirteenth of his mother's present age. The sum of the present ages of all three of them is 125 years. What is the difference between the present ages of Rajan's daughter and Rajan's mother ?

Severity: Warning

Message: Undefined property: stdClass::$answer

Filename: questions/index.php

Line Number: 181

Backtrace:

File: /var/www/html/application/views/questions/index.php

Line: 181

Function: _error_handler

File: /var/www/html/application/controllers/Questions.php

Line: 121

Function: view

File: /var/www/html/index.php

Line: 315

Function: require_once

Let Rajan's present age be '\(x \)' years.

Then his daughter's present age is = \(\frac{x}{3}\) years.

His mother's present age = \(\frac{13x}{9}\) years.

Now, according to the question,

\(\therefore x+\frac{x}{3}+\frac{13x}{9}=125\)

\(\Rightarrow x=\)\(\frac{125*9}{25}\)\(=45\)

Therefore, required difference = \(\frac{13x}{9}-\)\(\frac{x}{3}=13x -\)\(\frac{3x}{9}=\)\(\frac{10x}{9}\)

\(\Rightarrow \frac{10*45}{9}\)= 50 years

Loading…

- Number System
- H.C.F. & L.C.M.
- Decimal Fractions
- Simplification
- Square Roots & Cube Roots
- Average
- Problems on Numbers
- Problems on Ages
- Surds & Indices
- Percentage
- Profit & Loss
- Ratio & Proportion
- Partnership
- Chain Rule
- Time & Work
- Pipes & Cistern
- Time & Distance
- Problems on Trains
- Boats & Streams
- Alligation or Mixture
- Simple Interest
- Compound Interest
- Logarithms
- Area
- Volume & Surface Areas
- Mensuration
- Races & Games of Skill
- Calendar
- Clocks
- Stocks & Shares
- Permutations & Combinations
- Probability
- True Discount
- Banker’s Discount
- Heights & Distances
- Odd Man Out & Series
- Algebra