Question 11 & 12

Past Exam Questions 2017 0

Question 11: 5 years ago fathers age was three times of his son’s age. If son is now 30 years old what is his father’s age?

Federal Public Service Commission 2017 – 2nd batch

Solution:

Let five years ago;

Fathers age = x years

Son’s age = y years

So, as per statement of question;

Father’s age = 3 x Son’s age

$\Rightarrow x = 3y$

so after five years (present time) this relation will turn like this;

$\Rightarrow x+5 = 3(y+5)$

But at present son’s age is 30 years , so;

$\Rightarrow y+5=30$

Put in above;

$\Rightarrow x+5 = 3 \times 30$

$\Rightarrow x+5 = 90$

$\Rightarrow x= 90-5$

$\Rightarrow x= 80$

So, Fathers current age is 80 years;

Question 12: After spending 280 rupees 30 % of the total is left. What was before the expenditure?

Federal Public Service Commission 2017 – 2nd batch

Solution:

Let the amount before spending = x RS

so when 280 Rs are spent, the remaining amount will be ;

$=x-280$

According to question this amount should be equale to 30% of initial amount i-e;

$x-280= 30 % of ;x$

$x-280= \frac{30}{100} \times x$

$\Rightarrow x-280= \frac{3}{10} \times x$

$\Rightarrow 10 (x-280)= 3x$

$\Rightarrow 10 x-2800= 3x$

$\Rightarrow 7 x=2800$

$\Rightarrow x=400$

So the initial amount , i-e before spending — was Rs 400.

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