Basic numerical skills or quantitative aptitude is essential for every individual who aspires to become an administrator by coming out successful in Civil Services Exam..Some model problems are given below.
Quest. No(1)
The price of petrol increases from Rs.70 to Rs75 per litre.By what percentage a person can decrease the consumption of petrol so that his overall budget does not change ?
5x100 /70 = 7.14 %
Let the Priceof petrol be Rs x per litre.
Let the cosumtion be y.
Then,
Total expenditure = Rs. xy. per month.
Increased price= Rs1.0714x. per litre.
consumption = xy/1.10714x = 0.933y
Decreased consumption of petrol to tally his overall budget= 1-0.933=0.067=6.7%.
An easy method to solve..
Imagine a person consumes 30 liters petrol per month.
Then expenditure=Rs.30x70.=2100.
Present expenditure after hike=Rs.30x75=2250 .
Decreased consumtion to tally the budget=2lit=6.7%
Quest. No(1)
The price of petrol increases from Rs.70 to Rs75 per litre.By what percentage a person can decrease the consumption of petrol so that his overall budget does not change ?
5x100 /70 = 7.14 %
Let the Priceof petrol be Rs x per litre.
Let the cosumtion be y.
Then,
Total expenditure = Rs. xy. per month.
Increased price= Rs1.0714x. per litre.
consumption = xy/1.10714x = 0.933y
Decreased consumption of petrol to tally his overall budget= 1-0.933=0.067=6.7%.
An easy method to solve..
Imagine a person consumes 30 liters petrol per month.
Then expenditure=Rs.30x70.=2100.
Present expenditure after hike=Rs.30x75=2250 .
Decreased consumtion to tally the budget=2lit=6.7%
